Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• more accessible with methyl acrylate than with acrylonitrile. The lower reactivity of acrylamide in chloroform compared to methyl acrylate is in accordance with its lower electrophilicity. The observed rate reduction in methanol suggests the importance of the intramolecular hydrogen transfer pathway

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• the activity of CmaG (a putative FMN-dependent oxidoreductase), it is expected to catalyze the reduction of the keto group of an β-ketoacyl intermediate, similar to the ketoreductase of fatty acid synthase (FAS) and highly reducing type II PKS. This hypothesis is supported by the fact that cmaG exists

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• [90][91]. Due to their wide electrochemical window, imidazolium ILs are commonly used in organic electrochemistry, simultaneously as solvents and supporting electrolytes [92][93][94]. In addition, the cathodic reduction (both in batch [95] and in flow [96]) can be exploited for the generation of N

• investigation using lower amounts of BF3·Et2O revealed that a 92% yield of 2a could be realized using 3 equiv of the Lewis acid by extending the reaction time to 65 h (Table 1, entry 10). A further reduction in the amount of BF3·Et2O to 2 equiv resulted in a lower yield of 66% after the same reaction time (65 h

• -BF4, with an additional methyl group in 2 position of the imidazolic ring, gave 2a with a lower yield compared to BMIm-BF4 (Table 3, entry 6 vs 2). Replacing the imidazolium cation with 1-butyl-3-methylpyridinium led to a drastic reduction of the yield of 2a, to 35% (Table 3, entry 7). By keeping the

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• dimers reduce halides that have reduction potentials less cathodic than ca. −2 V vs ferrocenium/ferrocene, especially under UV photoexcitation (using a 365 nm LED). In the case of benzyl halides, the products are bibenzyl derivatives, whereas aryl halides are reduced to the corresponding arenes. The

• ; reduction; reductive dimerization; Introduction Reductive dehalogenation reactions of organic halides can be used in organic synthesis as a means of generating carbon-centered radical or anion intermediates and could have relevance to the treatment of waste halogenated polymers. While such reactions can be

• to initiate the coupling of aryl halides and arenes [5]. However, even relatively easily reduced organic halides have sufficiently cathodic reduction potentials (e.g., ca. −1.6 V and −1.8 vs ferrocenium/ferrocene (FeCp2+/0) for diethyl bromomalonate [6] and 4-iodotoluene, see Table 2, respectively

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• clear evidence of a bathochromic shift and a reduction in the optical band gap. These results support the idea that the introduction of biphenylene linkages may decrease delocalization in the structure. However, despite this reduction, there is still communication between the acene units evident from

• presence of two reduction potentials commonly observed in azaacenes, suggesting that the modification did not alter this characteristic feature. For compound 58a, λmax was observed at 600 nm, and λmax,em was at 614 nm. On the other hand, for compound 58b, λmax was found at 606 nm, and λmax,em occurred at

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• using ferrocene (Fc) as inner standard. The CV curves are shown in Figure 6 and the data are collected in Table 1. The reduction onset potentials (Ered,onset) of compounds 6–9 fall in the range from −1.63 to −1.47 V, while the onset values of the first oxidation wave range from 1.02 to 1.09 V. The

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• and visible–near infrared spectroscopy. The reaction of La@C2v-C82 with alkyl halides using the same conditions showed no consumption of La@C2v-C82, indicating that the reactivity of La@C2v-C82 toward alkyl halides was effectively increased by one-electron reduction. Single-crystal X-ray diffraction

• reaction is believed to occur via electron transfer, followed by the radical coupling of La@C2v-C82 and benzyl radicals, rather than by bimolecular nucleophilic substitution reaction of La@C2v-C82 anion with 1. Keywords: electron transfer; metallofullerene; radical; reduction; Introduction Fullerenes

• @C2v-C82. Moreover, the reaction was suppressed by the one-electron reduction of M@C2v-C82. These results suggest that oxidation and reduction reactions are useful for tuning the reactivity of metallofullerenes. Recently, remarkable reactivity of [M3N@Ih-C80]2− (M = Lu, Sc) toward benzal bromide was

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• %); bNMR yield; cstructure confirmed by single-crystal X-ray data; dcalculated yield based on incomplete conversion of NH-substrate. Examples of N-deprotection of α-modified glutarimides 1. Preparation of NH2-containing derivative 10 via reduction of 6n. Supporting Information Deposition number 2298240

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• /E isomers in approximately 85:15 ratio. The same spectra in CDCl3 showed broad coalescent signals for the characteristic vinyl CH protons, which is indicative of a dynamic equilibrium between the isomers. For both types of nitro intermediates 3 and 6 the final ring-forming step required reduction of

• conditions presented a challenge with regard to the chemoselectivity of the desired transformation, as they initially gave mixtures of 4-quinolones 5 or 8, respectively, and their corresponding N-hydroxy derivatives 4 or 7, respectively. Such a result is not surprising, considering that the reduction of the

• , because of concomitant reduction at the C–Cl bond. Intermediates 6, similarly to compounds 3, gave mixtures of products 7/8 under palladium-catalyzed transfer hydrogenation conditions. In contrast to 3, however, limiting the reaction time here did not help to develop a preparatively useful procedure for a

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• electron release. The radical intermediate A could then be captured by a series of different radical acceptors. Finally, the initial NaI/PPh3 complex I was regenerated from complex III through an electron injection/reduction process. This article aims to provide a comprehensive overview of the latest

• academic research and industrial applications. As a result, significant efforts have been devoted to the development of various methods for the reduction of nitroarenes [39]. Recent advancements in the catalytic reduction of nitroarenes largely rely on transition-metal catalysis through direct

• has emerged as an attractive approach for nitroarene reduction [43][44]. In 2021, Huang and colleagues discovered a photoredox system that did not require any transition metal or other photosensitizers [45]. This system employed a combination of NaI and PPh3 to achieve highly selective reduction of

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• concentration of this greenhouse gas by upcycling. Selectivity towards CO2-reduction products is highly desirable, although it can be challenging to achieve since the metal-hydrides formation is sometimes favored and leads to H2 evolution. In this work, we designed a cobalt-based catalyst, and we present herein

• its physicochemical properties. Moreover, we tailored a fully earth-abundant photocatalytic system to achieve specifically CO2 reduction, optimizing efficiency and selectivity. By changing the conditions, we enhanced the turnover number (TON) of CO production from only 0.5 to more than 60 and the

• ) complex; earth-abundant; hexafluoropropanol; photocatalytic CO2 reduction; Introduction Solar energy conversion into chemical energy addresses the issues of energy shortage with the exploitation of renewable sources [1]. Photoinduced CO2 reduction is included in the vast research field of artificial

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• -shifted in the film. These results indicate molecular π-stacking aggregation and excimer formation on the films [2]. The PL in film was obtained as a function of temperature (Figure 4). The observed reduction of the PL intensity on heating is expected for organic semiconductors due to self-quenching

• at the Colhex–Iso transition. The reduction of PL at the Cr–Colrect transition also reflects stronger molecular π-stacking of 2 in the Colrect phase compared to the crystalline state. The excited state lifetimes of 1 and 2 in chloroform solutions and spin-coated films, both excited at 401 nm, are

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• -phenylindoloquinoxaline (PhIQ) derivatives, shown in Figure 6 as Qx50 series, by chemically modifying the PhIQ groups. In particular, substituents at the 2- and 3-positions of PhIQs were introduced, allowing regulation of the reduction–oxidation potentials of the compounds. The PhIQs exhibited fluorescent solvatochromism

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• optoelectronic devices. The electrochemical behavior of TPECNz was analyzed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in CH2Cl2 containing 0.1 M n-Bu4NPF6 as a supporting electrolyte. As illustrated in Figure 5b, the molecule shows multiple quasi-reversible oxidation and reduction

• behavior in the potential window from −1.5 eV to 2.0 eV. The reduction wave appeared at a half-wave potential (E1/2) of −1.26 eV assigned to the reduction of an electron-deficient Nz core as observed in the calculated LUMO orbital [39]. The first oxidation wave occurred at E1/2 of 1.05 eV and was ascribed

• orbital. In addition, the oxidation and reduction onsets of TPECNz were 1.00 eV and −1.17 eV, respectively. Hence, the electrochemical energy gap (Egele) defined as the difference between the oxidation and reduction onset potentials was calculated to be 2.17 eV, which is slightly higher than the Egopt

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• , reacts more rapidly than any of the other dimers with VII via “electron-transfer-first”. Crystal structures show rather long central C–C bonds for 1b2 (1.5899(11) and 1.6194(8) Å) and 1h2 (1.6299(13) Å). Keywords: benzoimidazole; crystal structure; kinetics; n-dopant; reduction; Introduction Electrical

• strength and their reactivity with organic semiconductors (SC) does not depend solely on the SC reduction potential, since the first step, at least in many cases, is a hydride transfer rather than an electron transfer [8][9]. Moreover, as well forming the desired semiconductor radical anion SC•−, and the

• [12][13][16][19][26]. 1H derivatives can be obtained in a number of ways, including direct condensation of N,N'-dimethylphenylene-1,2-diamine derivatives with the appropriate aldehydes, YCHO [24][27], or borohydride reduction of 1+ salts [24]. The cations conversely can be obtained from 1H derivatives

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• crownphyrins 28–33 could be isolated. Upon reduction, the macrocycles demonstrated chloride binding (34a·(HCl)2; Figure 14). The presence of a dipyrrin unit within the crownphyrin molecules rendered them intriguing macrocyclic ligands. The reaction of 22a with lead(II) acetate provided a monomeric complex 22a

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• properties of the four CILs were probed using solution cyclic voltammetry (CV; Figure 4) and differential pulse voltammetry (DPV; Supporting Information File 1, Figures S27–S30), using dichloromethane as the solvent. For all reversible reduction or oxidation waves, HOMO and LUMO energy levels were determined

• using E1/2 values with Fc/Fc+ as the internal standard. All compounds exhibit two reversible reduction waves, where only PDIN-FB and PDIN-B exhibit a reversible oxidation wave. For CN-PDIN-FB and CN-PDIN-B, the HOMO is estimated using the optical band gap by subtracting the value in eV from the LUMO

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• diazonium salts produces highly reactive aryl radicals (Scheme 18) [153]. The chemical conversion can be initiated by electrochemical reduction [154], a reducing agent [155][156][157], a base [158], heating [159], or photochemically [160]. Aryl radicals may act as a halogen abstractor for alkyl halides and

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• , finally, the structure with the lowest energy, with the functional PBE0-D4/mTZVPP/CPCM. The Hartree–Fock plus London dispersion (HFLD) method was used for the study of non-covalent interactions (NCI). The calculations lead to the conclusion that a reduction in electrostatic interactions and an increase in

• the non-covalent interactions stabilizing the formation of 1:1 stoichiometry complexes was noted for the charge-transfer interactions. They are only slightly higher in CHCl3 than in DMSO, ranging from 1.4 to 2.9%. In general, it can be concluded from these calculations that the reduction of

• -covalent interactions in the appropriate solvent was assessed using the HFLD method. The calculations show that the reduction of electrostatic interactions and the increase in exchange and dispersion interactions in CHCl3 compared to DMSO are the driving forces for the placement of the sec-amine molecules

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• considered ways to further enhance this activity. We first explored the effects of structural modifications to berberine itself. The cationic iminium within berberine and its derivatives is susceptible to nucleophilic attack [10][14]. Through use of an acetone enolate, as well as partial or full reduction by

• typically less active when compared to the B1 variant. Exceptions to this were the markedly improved activity of compound B13 towards C. pseudodiphtheriticum, as well as its unique Gram-negative activity (Table 2). Given the partial reduction of berberine to B10 gave promising improvement for a single

• desired derivatives. Unexpected oxidation side-product B2, B4, and B6 were also isolated from certain reaction mixtures. Direct modification of the original berberine structure. Preparation of non-cyclic charged variants of B1. Partial reduction of compound B1 to B14. Synthesis of the substituted 2

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• Scheme 31. Initially, homolytic cleavage of thiosulfonate 70 generated PhS· and PhSO2· radicals. The reduction of Ni(II) to Ni(0) in the presence of Cs2CO3 and the reaction with 68 formed alkynyl-Ni species I. Then, the PhS· radical reacted with I to generate alkenyl radical II, which can react with the

• heterogeneous medium coming from H2O and toluene was beneficial for the progress of the transformation. In 2014, Denmark and Chi successfully synthesized a wide variety of pyrrolidines 99, piperidines 100, and azepanes via intramolecular sulfenoamination of olefins 98 (Scheme 40) [75]. The reduction of endo to

• reduction of II by silane. On the other hand, most of II were converted to intermediate III, which underwent hydride reduction to render product 140 (Scheme 61). Another organocatalysis system was disclosed by Liu and co-workers for sulfenylation of α-fluoro-β-ketoamides 143 and azlactones 145 (Scheme 62

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• complex 57 was obtained through reduction of the phenoxyimine-imidazolium bromide 55a (R = t-Bu) with NaBH4 followed by successive alkylation with iPrBr and reaction with Cu2O (Scheme 19) [32]. The use of the synthesized complexes 56a and 57 as precatalysts for the 1,4-conjugate addition to enones and the

• ]. Later in 2003, Buchwald, Sadighi and Jurkauskas [47] succeeded in the application of [(IPr)CuCl] as NHC–Cu(I) complex to catalyze the conjugate reduction of α,β-unsaturated carbonyl compounds. In the decade following these initial reports, the field has blossomed and NHC–Cu(I) complexes have been

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• the alkynyl-substituted 1,2-oxazin-4-ol derivative 19 which is smoothly available from the corresponding ketone 6 by highly stereoselective reduction with sodium borohydride [53]. Starting from 1,3- (8) or 1,4-bis(bromomethyl)benzene (16), respectively, the approved conditions in the presence of TBTA

• quantitatively available by sodium borohydride reduction of 7, we encountered the first problems. Under similar conditions of the hydrogenolysis the expected product 24 could be isolated as major component and characterized (Scheme 7, reaction 2), but the obtained sample contained unknown byproducts. It is

• reaction time and the fairly high amount of catalyst employed. As an alternative method, which should be more chemoselective, we examined the reduction with samarium diiodide [60]. This versatile one-electron transfer reagent is known to cleave N–O bonds with high selectivity [61][62] and was applied

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• ) reduction of intermediate H (Ered(NiI/Ni0) = −1.17 V vs SCE [41]) by photoexcited HE* (Ered(HE*/HE·+) = −2.28 V vs SCE [42]) regenerates the active Ni(0) species E and closes the catalytic cycle. Conclusion In conclusion, we have demonstrated a visible-light-induced nickel-catalyzed radical cross coupling

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• ) KO mouse which is a mouse model that stop the biosynthesis of ELs [22]. In that case, a reduction of the levels of various neurotransmitters were evidenced likely due to an alteration of the transport efficacy assumed by the synaptic vesicles. The phenotype of these KO mouse shows impaired social

• phosphoglycerolipids [30]. This is likely due to a reduction of the lateral area per molecule and an increase in lipid tail-ordering [31]. It must be however emphasis that the variability of the structure of the lipid chains can deeply influence the biophysical properties meaning that general conclusions could be

• phosphate moiety was introduced via the use of bromoethyl dichlorophosphate 11.4 to produce 11.5. The reduction of the ketone with NaBH4 produced 11.6, and then the incorporation of the trimethylammonium group produced deoxy-lyso-PAF 11.7. Finally, the acetylation of the secondary alcohol produced racemic