Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• ozonolysis to give aldehyde 136 [123]. Knoevenagel condensation with 4-iodooxindole was achieved in the next step. Pfitzner–Moffatt oxidation [124] followed by elimination furnished trans-divinylcycloproane 137. Submission of this compound to elevated temperature initiated a very smooth DVCPR yielding

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• Mukaiyama–Isayama peroxysilylation of unsaturated compounds, the Kobayashi cyclization, the nucleophilic addition of hydrogen peroxide to carbonyl compounds, the ozonolysis, and reactions with the involvement of peroxycarbenium ions. Each part of the review deals with a particular class of the above

• )cyclohexyl)propan-2-one) (58) in two steps. The latter was treated with p-TsOH to give the target peroxide 59 (Scheme 18) [252]. 1.3. The use of ozone. Peroxycarbenium ions in the 1,2-dioxolanes synthesis The ozonolysis of unsaturated compounds is a reliable and facile method for the introduction of the

• peroxide functional group. As in the above-considered studies, the intramolecular cyclization of ozonolysis products can be performed with the use of the hydroperoxide group provided that there is an appropriate electrophilic center. The reaction of oxetanes 60a,b with ozone in methanol produced 3-alkoxy

Towards stereochemical control: A short formal enantioselective total synthesis of pumiliotoxins 251D and 237A

• Jie Zhang,
• Hong-Kui Zhang and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2013, 9, 2358–2366, doi:10.3762/bjoc.9.271

• consisting of ozonolysis and reductive dehydroxylation provided the indolizidine derivative 5, which completed the formal enantioselective total synthesis of pumiliotoxins 251D and 237A. Keywords: enantioselective synthesis; Grignard reagent; pumiliotoxin 237A; pumiliotoxin 251D; reductive dehydroxylation

• form the indolizidinone ring. Thus, ozonolysis of olefin 22 in dichloromethane [51], followed by quenching with Me2S furnished the hemiaminal tautomer via intermediacy of lactam-aldehyde. Without isolation, the crude was subjected to the reductive dehydroxylation with Et3SiH/BF3·Et2O (CH2Cl2, −78 °C

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• ozonolysis and acid-promoted cyclization afforded (+)-41 and (−)-41 in an overall yield of 60% and 46%, respectively. For the synthesis of staurosporinone (30) and its 3,4-dimethoxybenzyl (DMB)-protected derivative 45, a ruthenium-catalyzed C–H insertion/electrocyclization cascade using 2,2’-bisindole 44 and

The preparation of several 1,2,3,4,5-functionalized cyclopentane derivatives

• André S. Kelch,
• Peter G. Jones,
• Ina Dix and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 1705–1712, doi:10.3762/bjoc.9.195

• excellent yield [7]. This bicyclic adduct was converted by ozonolysis followed by LAH reduction into the all-cis-derivative 15, whose benzyl ether protection group was finally removed by catalytic hydrogenation over palladium on carbon [7][8]. The full experimental details and the complete set of the

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• . Ozonolysis of the pendant olefin afforded aldehyde 75 in high yield. Following the prior procedure, the lithium enolate of TMS ester 64 was reacted with aldehyde 75, and the mixture of diastereomeric alcohols was oxidized to the β-ketoester 76 (Scheme 20). This substrate did not appear to be prone to

Re₂O₇-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

• Wantanee Sittiwong,
• Michael W. Richardson,
• Charles E. Schiaffo,
• Thomas J. Fisher and
• Patrick H. Dussault

Beilstein J. Org. Chem. 2013, 9, 1526–1532, doi:10.3762/bjoc.9.174

• were curious about the interactions of Re(VII) oxides with hydroperoxyacetals (1-alkoxyhydroperoxides), versatile intermediates available from ozonolysis of alkenes in alcoholic solvents [23][24]. As can be seen in Table 8, Re2O7, Me3SiOReO3 and PTSA all catalyze alkoxide metathesis to furnish a

• lack of reactivity of ozonolysis-derived 1-methoxyhydroperoxides towards methanolic acid may mask a rapid degenerate exchange [27]. The failure of the perrhenate to catalyze formation of N,O-acetals was initially perplexing. However, reported perrhenate-promoted dehydrations of amides and oximes

Camera-enabled techniques for organic synthesis

• Steven V. Ley,
• Richard J. Ingham,
• Matthew O’Brien and
• Duncan L. Browne

Beilstein J. Org. Chem. 2013, 9, 1051–1072, doi:10.3762/bjoc.9.118

• from purple to brown (d). (a) Ozonolysis of a series of alkenes using ozone in a bottle-reactor; (b) Glaser–Hay coupling using oxygen gas in the second-generation reactor. Cartridges containing polymer supported (PS) reagents are used to scavenge residual reagents: thiourea (TU) sequesters copper, and

Alternaric acid: formal synthesis and related studies

• Michael C. Slade and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2013, 9, 166–172, doi:10.3762/bjoc.9.19

• acetonide formation provided 7, and ozonolysis afforded Ichihara’s aldehyde 8 (Scheme 3). Interception of this intermediate thus constituted a formal synthesis; the precedent for the C8–C9 olefination involved a classical, three-step Julia olefination sequence [24]. To demonstrate proof-of-concept for a

Influence of cyclodextrin on the solubility of a classically prepared 2-vinylcyclopropane macromonomer in aqueous solution

• Helmut Ritter,
• Jia Cheng and
• Monir Tabatabai

Beilstein J. Org. Chem. 2012, 8, 1528–1535, doi:10.3762/bjoc.8.173

• with a Viscotek GPCmax VE2001 using DMF as the eluent at 60 °C (flow rate: 1 mL/min). The ozonolysis was carried out on an ozone generator by Fischer Technology. In this ozone generator 45–50 liters of oxygen per hour was provided. Synthesis of amino-terminated poly(N-isopropylacrylamide) 3 A) In water

• was calculated; in this case ca. 500 mg, corresponding [Me2-β-CD]/[5] ratio of about 0.02:1. Ozonolysis of copolymer 8 A condensation trap with 1 g of copolymer 8 is filled up with methanol until the inlet is immersed in the solution. The cold trap is connected with the ozone generator and flushed

• with nitrogen for 10 min. Then, the solution is cooled to −74 °C and finally flushed with oxygen. After starting the ozone generator the oxygen is converted to ozone. The ozonolysis continues until the solution turns blue due to the excess of ozone. After shutting off the ozone generator, the solution

Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part I: Dihydronepetalactones

• Nicole Zimmermann,
• Robert Hilgraf,
• Lutz Lehmann,
• Daniel Ibarra and
• Wittko Francke

Beilstein J. Org. Chem. 2012, 8, 1246–1255, doi:10.3762/bjoc.8.140

• the key intermediate 16 – which shows two differentiated primary alcohol functions – started from enantiomerically pure (R)-limonene (14, Scheme 2). Ozonolysis followed by reductive workup with dimethyl sulfide produced (3R)-3-(1-methylethenyl-6-oxoheptanal), which yielded the formyl cyclopentene 15

2-Allylphenyl glycosides as complementary building blocks for oligosaccharide and glycoconjugate synthesis

• Hemali D. Premathilake and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2012, 8, 597–605, doi:10.3762/bjoc.8.66

• can be reverted as needed (active–latent strategy). Direct conjugation of the AP moiety to biomolecules, monolayers, arrays, etc., should be possible by executing thiol–ene chemistry [43], ozonolysis/reductive amination [44][45][46], or other ligation protocols [47][48]. Experimental General remarks

Homoallylic amines by reductive inter- and intramolecular coupling of allenes and nitriles

• Peter Wipf and
• Marija D. Manojlovic

Beilstein J. Org. Chem. 2011, 7, 824–830, doi:10.3762/bjoc.7.94

• methodology, we demonstrated that the homoallylic amine products could be readily converted to synthetically useful building blocks, such as β-amino acids (Scheme 4). N-Boc-protection of the primary amine 12 followed by ozonolysis under Marshall’s conditions [40] yielded the β-amino acid derivative 24. The

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• considering a twist-boat transition state model in which the gold center and the allylic benzyloxymethyl substituents both occupy axial positions in order to avoid 1,3-allylic strain with the vinylic methyl groups. The isopropylidene group in compound 60 can be cleaved by ozonolysis to give the corresponding

The arene–alkene photocycloaddition

• Ursula Streit and
• Christian G. Bochet

Beilstein J. Org. Chem. 2011, 7, 525–542, doi:10.3762/bjoc.7.61

• to the desired compound via a thermal vinylcyclopropane–cyclopentene rearrangement. All obtained photocycloaddition compounds can be converted into the target by this means. The cyclopropane ring was opened by a Birch-type reduction. Oxidation of the primary alcohol and ozonolysis of the double bond

Molecular rearrangements of superelectrophiles

• Douglas A. Klumpp

Beilstein J. Org. Chem. 2011, 7, 346–363, doi:10.3762/bjoc.7.45

• ). Isomerization of 2-decalone (51). Rearrangement of the acyl-dication 58. Reaction of dialkylketone 64. Ozonolysis in superacid. Rearrangement of 1-hydroxy-2-methylcyclohexane carboxylic acid (79) in superacid. Isomerization of the 1,5-manxyl dication 87. Energetics of isomerization. Rearrangement of dication 90

Dipyridodiazepinone derivatives; synthesis and anti HIV-1 activity

• Nisachon Khunnawutmanotham,
• Nitirat Chimnoi,
• Arunee Thitithanyanont,
• Patchreenart Saparpakorn,
• Kiattawee Choowongkomon,
• Pornpan Pungpo,
• Supa Hannongbua and
• Supanna Techasakul

Beilstein J. Org. Chem. 2009, 5, No. 36, doi:10.3762/bjoc.5.36

• bromo compounds 18. The diazepinone ring was formed by treatment with sodium hexamethyldisilazane in pyridine to yield tricyclic compounds 19. Coupling of 19 with vinyltributyltin in the presence of tetrakis(triphenylphosphine) palladium(0) provided 8-vinyl compounds 20 which underwent ozonolysis to

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• exocyclic olefin was then converted to the corresponding ketone through ozonolysis. The ozonide and N-oxide were reduced with dimethyl sulfide at the end of the reaction. Using the Gardner protocol [96] to hydroxylate the alpha position of the resultant ketone failed to give any α-ketol, but instead

An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens

• Kirsti Parikka and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2009, 5, No. 22, doi:10.3762/bjoc.5.22

• -dimethoxybenzaldehyde (18–48% yields whenever reported) [22][23][24][25][26]. Additional synthetic methods have been developed for shorter chain AR (ozonolysis product of a pentadecylresorcinol (C15

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• THF unit 140 was then constructed by ozonolysis of the alkenol 137 to give the lactol 138. Treatment of 138 with an excess of propargyl alcohol afforded 139, which was followed by anomeric O-C rearrangement to give 140. The hetero-Diels-Alder (HDA) reaction between diene 141 and nitrosobenzene

Synthesis of chiral cyclohexanes and carbasugars by 6-exo-dig radical cyclisation reactions

• Rajeev K. Shrivastava,
• Elise Maudru,
• Gurdial Singh,
• Richard H. Wightman and
• Keith M. Morgan

Beilstein J. Org. Chem. 2008, 4, No. 43, doi:10.3762/bjoc.4.43

• the “methyl” analogues 28 and 29 and these gave a similar outcome, (Scheme 6 and Scheme 5). Ozonolysis of the pair of geometric isomers 30 and 31 afforded the protected ketone 38 in 77% yield. The diastereomeric ketone 39 was obtained in 74% yield after similar treatment of 32 and 33. Removal of the

End game strategies towards the total synthesis of vibsanin E, 3-hydroxyvibsanin E, furanovibsanin A, and 3-O-methylfuranovibsanin A

• Brett D. Schwartz,
• Craig M. Williams and
• Paul V. Bernhardt

Beilstein J. Org. Chem. 2008, 4, No. 34, doi:10.3762/bjoc.4.34

• ) by a Claisen rearrangment (via the silyl enol ether) was not high yielding and produced many side products. Ozonolysis of 25 afforded the acetone sidechain (i.e. 26) in acceptable yield (50%). Other methods to unmask the ketone functionality failed, for example, dihydroxylation followed by oxidative

Total synthesis of the indolizidine alkaloid tashiromine

• Stephen P. Marsden and
• Alison D. McElhinney

Beilstein J. Org. Chem. 2008, 4, No. 8, doi:10.1186/1860-5397-4-8

• desired aldehyde to undergo retro-Mannich fragmentation, and so elected to carry out a reductive work-up to the ozonolysis procedure (Scheme 3). The desired alcohol 8 was obtained in a crude form and immediately subjected to reduction with lithium aluminium hydride to give our target tashiromine 1 in 36

Facile synthesis of two diastereomeric indolizidines corresponding to the postulated structure of alkaloid 5,9E- 259B from a Bufonid toad (Melanophryniscus)

• Angela Nelson,
• H. Martin Garraffo,
• Thomas F. Spande,
• John W. Daly and
• Paul J. Stevenson

Beilstein J. Org. Chem. 2008, 4, No. 6, doi:10.1186/1860-5397-4-6

• magnesium iodide gave the water soluble tertiary alcohol 1 in 96% yield. 7-Oxoheptanoic acid methyl ester was prepared by the literature procedure [36], by ozonolysis of 1-methoxycycloheptene, and then condensed with the amidoalcohol 1 with azeotropic removal of water to give the N,O-acetal 2 in 71% yield

Synthesis of the Benzo- fused Indolizidine Alkaloid Mimics

• Daniel L. Comins and
• Kazuhiro Higuchi

Beilstein J. Org. Chem. 2007, 3, No. 42, doi:10.1186/1860-5397-3-42

• 14 in 22% yield. The furan ring of 8a was converted to a carboxylic acid by ozonolysis to afford 15. The reductive amination of 8a with benzylamine provided 16α and 16β in good yield. The stereochemistry of these compounds was determined by NOESY NMR analysis. These functional groups, such as