A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• alkene in the side chain [56] for which the reaction catalyzed by the same capsule led to the protonation of the alkene unit with an intramolecular nucleophilic attack by the alcohol moiety forming a final cyclic ether product. In the latter case the tertiary alcohol could not easily eliminate water and

The enzyme mechanism of patchoulol synthase

• Houchao Xu,
• Bernd Goldfuss,
• Gregor Schnakenburg and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

• three Me groups, four olefinic carbons (two quarternary, one CH and one CH2), and a tertiary alcohol, suggesting the structure of an oxidised (dehydrogenated) bicyclic sesquiterpene alcohol (Figure 4). The 1H,1H-COSY spectrum revealed one large contiguous spin system C-2-3-4(15)-5-6-7-8-9. HMBC

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• (Figure 15). Next, ring-expanding rearrangement is proposed to form 75. Finally, the C7 ketone is reduced, the C8–C9 bond is oxidized back to an alkene, the C5–C6 double bond is oxidized to an epoxide, and C15 is oxidized to a tertiary alcohol to yield 72. The authors not only structurally characterized

Allylic alcohols and amines by carbenoid eliminative cross-coupling using epoxides or aziridines

• Matthew J. Fleming and
• David M. Hodgson

Beilstein J. Org. Chem. 2021, 17, 2385–2389, doi:10.3762/bjoc.17.155

• , α-methoxyhexyllithium derived from stannane 7 [14][15] was reacted with terminal epoxide 5, which gave the allylic alcohol 8 (79%, E/Z = 73:27, Scheme 4). This organolithium also proved reactive with 2,2-disubstituted epoxide 9, giving allylic tertiary alcohol 10 (72%, E/Z = 82:18). A trisubstituted

Recent advances in Cu-catalyzed C(sp³)–Si and C(sp³)–B bond formation

• Balaram S. Takale,
• Ruchita R. Thakore,
• Elham Etemadi-Davan and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• silane PMHS gave only trace amounts of the product. The nature of the alcoholic protonation reagent also had a strong impact. The presence of a tertiary alcohol, t-AmOH or t-BuOH, was essential for the reaction to occur with a reasonable yield, while iPrOH and MeOH markedly suppressed the reaction (Table

Combination of multicomponent KA² and Pauson–Khand reactions: short synthesis of spirocyclic pyrrolocyclopentenones

• Riccardo Innocenti,
• Elena Lenci,
• Gloria Menchi and
• Andrea Trabocchi

Beilstein J. Org. Chem. 2020, 16, 200–211, doi:10.3762/bjoc.16.23

• one-pot, resulting in the generation of the stereochemically dense epoxyalcohol 37 in 68% overall yield. The treatment of compound 5 with EtMgBr as a Grignard reagent in the presence of CeCl3 gave the corresponding tertiary alcohol 38 with similar stereochemical features as of 36 in the formation of

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

• Katarzyna Włodarczyk,
• Piotr Borowski and
• Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

• dissociation are ca. 34.6 kcal/mol for the secondary alcohol 8, ca. 23.3 kcal/mol for the mesylate 60, and ca. 25.0 kcal/mol for the tertiary alcohol 20, as estimated by DFT calculations. The value for mesylate roughly fitted the range according to which the reaction may proceed at room temperature. For

• , leading to intermediate I, and the overall transformation proceeded with remarkable stabilization. In the next step, dissociation of the C−O bond occurred through transition state II, finally leading to alkene III. The activation energy for the C−O bond cleavage in 20, a tertiary alcohol, was similar to

• , mesylate (SP)-60, and alkenylphosphine sulfide (SP)-65 were subjected to the reaction with Lewis-acidic AlCl3 (Scheme 12). Rearrangement of the tertiary alcohol (SP)-17 proceeded very efficiently, affording the corresponding product in high yield. Unfortunately, the stereoselectivity of the reaction

Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.

• Annika Stein,
• Dave Compera,
• Bianka Karge,
• Mark Brönstrup and
• Jakob Franke

Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196

• (δH 3.37 (H-6)), and a tertiary alcohol at C-14 (δC 80.9 ppm). COSY correlations supported by HMBC analysis (Figure 2A) revealed an intact ABCD ring system with a substitution pattern identical to 4β-hydroxywithanolide E (1). Only a single, striking difference was noted: C-17 was shifted from 87.8 to

A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

• András György Németh,
• György Miklós Keserű and
• Péter Ábrányi-Balogh

Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155

• %, respectively) that might be attributed either to steric hindrance or the growing instability of the conjugate base of the secondary and tertiary alcohol, respectively. The present method provided the allylic derivative 3j in 72% yield, however, applying ethylene glycol resulted in 3k in 34% yield only. In the

Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids

• Herman O. Sintim,
• Hamad H. Al Mamari,
• Hasanain A. A. Almohseni,
• Younes Fegheh-Hassanpour and
• David M. Hodgson

Beilstein J. Org. Chem. 2019, 15, 1194–1202, doi:10.3762/bjoc.15.116

• selective deprotection in α-diazo ester 23 in the presence of the tertiary TBS ether. It was considered important that the tertiary alcohol remain masked during projected oxidation of the released secondary alcohol to give the ketone functionality in the cycloaddition substrate, as otherwise essentially

• group strategy led us to TES protection at both alcohols, on the basis that this group should be robust enough to withstand the enolate manipulation chemistry, that desilylation of the secondary TES ether during acetonide removal could be restored in the subsequent tertiary alcohol silylation step, that

Synthesis of eunicellane-type bicycles embedding a 1,3-cyclohexadiene moiety

• Alex Frichert,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2018, 14, 2461–2467, doi:10.3762/bjoc.14.222

•  3). For the synthesis of 25, we started from the known limonene oxide-derived diol 20 [24] that was hydrogenated, oxidized, and silylated at the tertiary alcohol moiety (81%). Reaction of deprotonated 21 with ethyl cyanoformate afforded cyanohydrin 22 by attack of liberated cyanide at the carbonyl

• the relative configuration shown in Scheme 4. From cyanohydrin 22 HCN was eliminated by treatment with diluted NaOH (100%, Scheme 3). The resulting ketone 23 reacted with lithiated alkyne 12 affording diastereomerically pure tertiary alcohol 24 (63%) that showed a broad hydroxy signal in the 1H NMR

• , treatment of 25 with TiCl4/Zn did not lead to pinacol cyclization and we have evidence that the aldehyde group stayed in place and the keto group had been reduced. Installation of a TMS group at the tertiary alcohol moiety of 25 (TMSOTf, 2,6-lutidine) formed 26, which was simply reduced at the keto function

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• 2c, respectively, were compatible with the reaction conditions. For the carboxylation of tertiary-alcohol-derived acetates to the corresponding carboxylic acids 2d,e, CoI2(bpy) was found to be an effective catalyst. The yields of product 2 decreased when less bulky substituents (R1) were used. Thus

Cobalt bis(acetylacetonate)–tert-butyl hydroperoxide–triethylsilane: a general reagent combination for the Markovnikov-selective hydrofunctionalization of alkenes by hydrogen atom transfer

• Xiaoshen Ma and
• Seth B. Herzon

Beilstein J. Org. Chem. 2018, 14, 2259–2265, doi:10.3762/bjoc.14.201

• the tertiary alcohol 4f in 69% yield (Table 1, entry 6). Inspired by Girijavallabhan and co-workers’ report [10], we were able to trap the tertiary alkyl radical with S-phenyl benzene thiosulfonate (PhSO2SPh, Table 1, entry 7) and Se-phenyl 4-methylbenzenesulfonoselenoate (TsSePh, Table 1, entry 8) [3

Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents

• Ugo Azzena,
• Massimo Carraro,
• Gloria Modugno,
• Luisa Pisano and
• Luigi Urtis

Beilstein J. Org. Chem. 2018, 14, 1655–1659, doi:10.3762/bjoc.14.141

•  1). Finally, the tetrahydropyranylation of a tertiary alcohol 1j as well as of phenols 1k and 1l required, besides the employment of 2.0 equiv of DHP, relatively longer reaction times and higher temperatures. It is worth noting that under our mild reaction conditions we did not observe any

• , the mixture obtained by reacting 1f with 1.1 equiv of 2 and 3 mol ‰ of NH4HSO4@SiO2 in 2-MeTHF under dry Ar was filtered and dropwise added to a vigorously stirred freshly prepared solution of EtMgBr in the same solvent at rt. Aqueous work-up and flash chromatography afforded the desired tertiary

• alcohol 4fa in 78% yield (Scheme 4). Under similar conditions, protection of 1f in CPME, followed by filtration and dropwise addition of the resulting solution to a suspension of LiAlH4 in the same solvent, afforded the monoprotected diol 4fb in almost quantitative yield (Scheme 5). Conclusion The above

Investigations of alkynylbenziodoxole derivatives for radical alkynylations in photoredox catalysis

• Yue Pan,
• Kunfang Jia,
• Yali Chen and
• Yiyun Chen

Beilstein J. Org. Chem. 2018, 14, 1215–1221, doi:10.3762/bjoc.14.103

• (Scheme 4). Tertiary alcohols 6 were reported to be activated by cyclic iodine(III) reagents under photoredox conditions to generate alkoxyl radicals, and subsequently underwent β-fragmentation and alkynylation to yield 7 after eliminating the arylketone [25]. With tertiary alcohol 6a as the alkyl radical

• derivatives for radical alkynylations in photoredox catalysis. Reaction conditions: tertiary alcohol 6 (0.25 mmol, 2.5 equiv), alkynylbenziodoxole 3 (0.10 mmol, 1.0 equiv), Ru(bpy)3(PF6)2 (0.002 mmol, 0.02 equiv), and BI-OAc (0.25 mmol, 2.5 equiv) in 2.0 mL DCE for 24 h under a nitrogen atmosphere, unless

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• have so far been reported [7][28][29][30]. In 2007, Gosselin and Britton et al. reported that treatment of ethyl trifluoropyruvate (1a) with (R)-BINOL-mediated organozincate as a chiral methylating regent provided the corresponding methylated tertiary alcohol 2a in moderate enantioselectivity (Scheme 1

From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• -type double bonds in the bisdioxines under acidic conditions generates a tertiary alcohol, which again undergoes a transannular oxa-Michael-type ring closure forming a tetraoxaadamantane. Free carboxylic acid functions are decarboxylated in this process (Scheme 7), but amide and ester functions are

Acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with alcohols

• Katrina Tait,
• Alysia Horvath,
• Nicolas Blanchard and
• William Tam

Beilstein J. Org. Chem. 2017, 13, 2888–2894, doi:10.3762/bjoc.13.281

• reactions. The scope of the reaction was successfully expanded to include primary, secondary, and tertiary alcohol nucleophiles. Through X-ray crystallography, the stereochemistry of the product was determined which confirmed an SN2-like mechanism to form the ring-opened product. Keywords: acid catalysis

• product (Table 3, entry 9). The cyclic alcohols cyclohexanol and cyclopentanol (Table 3, entries 10 and 11) produced low amounts of the ring-opened alcohol in a 24% and 26% yield, respectively. The use of a tertiary alcohol surprisingly resulted in a moderate yield, with tert-butanol producing a 50% yield

• of the reaction was successfully expanded to include primary, secondary, and tertiary alcohol nucleophiles. Through X-ray crystallography, the stereochemistry of the product was determined which confirmed an SN2-like mechanism to form the ring-opened product. Further investigation of the ring-opening

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• and subsequent column chromatography. All compounds 3 showed a characteristic pair of doublets between 3 and 4 ppm with a large geminal 2J coupling of 12–16 Hz for the benzylic methylene group (-CH2Ar) in their 1H NMR spectra and a singlet at 90 ± 3 ppm for the newly formed tertiary alcohol (C–OH) in

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• in the presence of an aryl or an alkyl group. The number of methylene units between the alkene and the tertiary alcohol function was studied: n = 0, 2, and 3 were suitable for generating thermodynamically favoured 3, 5, and 6-membered cyclic transition states; the reaction failed with n = 1, 4

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• nearly 90% yields for α-amino esters in 90–120 min (Scheme 18). The Ritter reaction is another significant carbon–nitrogen (C–N) bond forming reaction in the synthesis of amides [86]. Generally, a nitrile and a tertiary alcohol in presence of a strong acid react to create amides. Major drawbacks

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• coincide in 13 but are approximately 2 ppm apart in 12. Compounds 12 show a signal for the C=O near 206 ppm and one for the sulfonamide carbon at about 65 ppm. In compounds 13, there is a signal for the C=N around 194 ppm and one for the tertiary alcohol carbon near 73 ppm. All other signals of the camphor

Revaluation of biomass-derived furfuryl alcohol derivatives for the synthesis of carbocyclic nucleoside phosphonate analogues

• Bemba Sidi Mohamed,
• Christian Périgaud and
• Christophe Mathé

Beilstein J. Org. Chem. 2017, 13, 251–256, doi:10.3762/bjoc.13.28

• loss of AcOH leading to compound (+/−)-15 with 85% yield. The 1,3-allylic transposition of the hindered tertiary alcohol group under acidic conditions has not been reported yet for such compounds. It may conceivably that such a transposition occurs through the formation of an allylic carbocation which

Chromium(II)-catalyzed enantioselective arylation of ketones

• Gang Wang,
• Shutao Sun,
• Ying Mao,
• Zhiyu Xie and
• Lei Liu

Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275

• -catalyzed enantioselective addition of aryl halides to both arylaliphatic and aliphatic ketones with high enantioselectivity in an intramolecular version, providing facile access to enantiopure tetrahydronaphthalen-1-ols and 2,3-dihydro-1H-inden-1-ols containing a tertiary alcohol. Keywords: arylation

• ; asymmetric catalysis; chromium; ketone; tertiary alcohol; Introduction Catalytic enantioselective carbon–carbon bond formation reactions have achieved enormous development during the last few decades as a consequence of the growing demand for enantiopure compounds in modern industry, especially the

• -catalyzed enantioselective arylation of ketones has never been reported to date [44]. Tetrahydronaphthalen-1-ol bears a chiral tertiary alcohol center and is a common structural motif in numerous biologically active natural products and clinical drugs [45]. The method to prepare these compounds through