Reduction of Carbonyl Compounds by Sodium Borohydride Adsorbed on Alumina

Santaniello, Enzo; Ponti, Federico; Manzocchi, Ada

doi:10.1055/s-1978-24927

Cited by 42 publications

(19 citation statements)

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“…The known 12 ketone 13 on methylation afforded the methylated ketone 14 (Scheme 3) whose transformation to the diene 15 was accomplished by reduction, tosylation and detosylation respectively. The α,β-unsaturated ketone obtained by oxidation of the diene 15 on cyanation and reduction respectively yielded an aldehyde which was further reduced 13 …”

Section: Methodsmentioning

confidence: 99%

Reagents for the synthesis of alkenes from carbonyl compounds: applications in the synthesis of terpenoid compounds

Vera¹,

Laya²,

Poon³

et al. 2013

Arkivoc

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Section: Methodsmentioning

confidence: 99%

Reagents for the synthesis of alkenes from carbonyl compounds: applications in the synthesis of terpenoid compounds

Vera¹,

Laya²,

Poon³

et al. 2013

Arkivoc

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“…However, success was achieved in the vinylation by this method of a A4-3-keto steroid lacking a C19 (20) with lithium divinylcuprate -tri-n-butylphosphine complex gave a product that is assigned structure 21. Its gross structure follows from its ir (2.80 (w), 5.86,6.08 (w), 10.1 (w), 10.90 (w) pm), uv (272-282 nm (E 21)), and 'H nmr spectra (6 0.80 (s, 3H), 3.5-3.8 (m, lH), 4.8-6.0 (m, 3H)).…”

Section: Ots C3h7mentioning

confidence: 99%

“…Chromatography on a silica gel column with elution with hexanelethvl acetate 19:l vlv and 4:l vlv) afforded three fractions: unconsumed 24 (147mg), 31 (326 mg, 41%), and 32 (57 mg, 7%). "Prepared by addition of a sluny of NaBH, (1.0g) in distilled water (1.0mL) to neutral alumina (log); the mixture was stirred for 6 h until it was homogeneous and dried overnight in uacuo (20).…”

Section: Thermolysis Of 24 Formation Of 2p5-(syn-methylmethano)-mentioning

confidence: 99%

“…Attempts to improve the yield of the ene reaction by protection tert-butyldimethylsilyl ether were unsuccessful. However, thermolysis of the corresponding dione 24 proceeded much more smoothly to give a 41% yield of a product assigned structure 31 on the basis of its spectroscopic properties (as in the case of 30, g H CH3 the signal of the C1' methyl group is readily m/e 302 discernible in the 'H nmr spectrum of the product at 6 0.88 (d, J = 8Hz)) and the fact that it is selectively reduced by sodium borohydride adsorbed on alumina (20) to 30 and is formed on chromic acid oxidation of the latter. Compound 31 was also formed in significant amount (-10%) on thermolysis of 21 when the decalin solution was not carefully freed of oxygen, presumably resulting from oxidation of the C17 hydroxyl group by decalin hydroperoxide formed by oxidation of decalin at 350°C.…”

mentioning

confidence: 99%

“…In order to determine this it was necessary to remove the C17 carbonyl group, and this was accomplished by selective reduction to 34 with sodium borohydride adsorbed on alumina (20). The mass spectrum of the product showed it to be a dihydro compound and the fact that the C 17 rather than the C3 carbonyl group is reduced is evidenced by a shift of the C 18 methyl signal from 6 0.90 in the 'H nmr spectrum of 32 to 6 0.80 in that of 34 (22) and by the retention of enhanced n + n*.…”

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confidence: 99%

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Bridged-ring steroids. II. The synthesis of bridged steroids with a bicyclo[2.2.1]heptane ring A system

Yates¹,

Winnik²

1981

Can. J. Chem.

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PETER YATES and FRANFOISE M. WINNIK. Can. J. Chem. 59, 1641 (1981).Bridged steroids with a bicyclo[2.2.l]heptane ring A system are formed on thermolysis of 5-vinyl 3-keto steroids. 5-Vinyl-Sa-cholestan-3-one (26) on being heated at 350°C in decalin gave 2a,5-(syn-methylmethano)-Sa-cholestan-3-one (27). Similar treatment of 17~-hydroxy-S-vinyl-S~-estran-3-one (21) gave 17P-hydroxy-2P,5-(syn-methylmethano)-SP-estran-3-one (M), which was also obtained by reduction of 2P,S-(syn-methylmethano)-SP-estrane-3,17-dione (31) with sodium borohydride on alumina. Compound 31 was formed as the major product on thermolysis of 5-vinyl-5P-estrane-3,17-dione (24) at 350°C, together with 5-(trans-propeny1)-A-nor-SP-estrane-3,17-dione (32). Compounds 27, 30, and 31 are considered to arise via intramolecular ene reactions of the A*-enols of compounds 26, 21, and 24, respectively. Compound 32 is postulated to be formed via an analogous reaction of the A3-enol of 24, followed by thermolysis of the resulting 3'-methyl-4~,5-dihydrocyclopropa[4,5]-5~-estrane-3,17-dione (36). Photolysis of 30 in methanol results in a-cleavage of the C2-C3 bond and the formation of a ketene-derived ester and two enal-derived oxetanes.PETER YATES et FRAN~OISE M. WINNIK. Can. J. Chem. 59, 1641 (1981). La thermolyse des vinyl-5 ceto-3 stero~des conduit a la formation de stero~des pontes portant au niveau du cycle A un bicyclo[2.2.1] heptane. Si on chauffe la vinyl-5 5a-cholestanone-3 (26) dans de la decaline a 350"C, on obtient la (methylmCthano syn)-2a,5 5a-cholestanone-3 (27). L'hydroxy-17P vinyl-5 SP-estranone-3 (211, traitee de la mime f a~o n , fournit I'hydroxy-17P (methylmethano syn)-2P,5 SP-estranone-3 (30) que I'on obtient egalement par reduction de la (methylmethano syn)-2P,S SP-estraned~one-3,17 (31) par le borohydrure de sodium sur I'alumine. Le composk 31 se forme comme le produ~t principal de la thermolyse de la Bridged steroids are of interest both because of their potential biological activity and because they can serve as substrates for the study of the effects of the constraints imposed on bridged bicyclic systems by the steroid skeleton in the course of the I reactions of such systems.We and others have previously investigated the synthesis of steroids incorporating a bicyclo-[2.2.2]octane (2, and references therein quoted) or bicyclo[3.2. ]]octane system (3). Here we are concerned with the incorporation of a bicyclo-[2.2.l]heptane system. Solo et al. have made extensive investigations of bridged ring D steroids of this type, which they synthesized by Diels-Alder addition of dienophiles to steroid 14,16-dienes (4, and earlier papers in this series). However, the only previous work to our knowledge that led to the incorporation of a bicyclo[2.2. llheptane system into a steroid ring other than ring D is that of Nazer ( 9 , who obtained compounds la and l b by treatment of 2a and 2b, respectively, with lithium (3), C2 and C5 (4), or C3 and C10 (5) (the last being possible only in the 19-nor series). Our initial approach was to a system of typ...

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Tritium and deuterium labelling studies of alkali metal borohydrides and their application to simple reductions

Than

Morimoto

Andres

et al. 1996

J Label Compd Radiopharm

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SummarySimple and facile syntheses of highly deuterated and tritiated LiBH4, NaBH4 and KBH4 were achieved by hydrogen isotope exchange with deuterium or tritium gas at elevated temperatures. The exchange products were characterized by boron, proton and deuterium or tritium NMR spectroscopy. The extent of isotope (2H or 3H) incorporation was calculated from the patterns of *lB NMR spectra. Several samples of tritiated NaBH4 were treated with BF3-Et20 to produce tritiated borane-THF complex, which is an electrophilic reducing agent. The utility of both the borohydride reagents and borane-THF complex in labelling reactions was confirmed by exemplary reductions leading to specifically labelled products. The extent and orientation of labelling in the reduction products was assessed by a combination of radio-HPLC analysis, 1H, *H or 3H NMR and mass spectrometry.

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Reduction of Carbonyl Compounds by Sodium Borohydride Adsorbed on Alumina

Cited by 42 publications

References 0 publications

Reagents for the synthesis of alkenes from carbonyl compounds: applications in the synthesis of terpenoid compounds

Reagents for the synthesis of alkenes from carbonyl compounds: applications in the synthesis of terpenoid compounds

Bridged-ring steroids. II. The synthesis of bridged steroids with a bicyclo[2.2.1]heptane ring A system

Tritium and deuterium labelling studies of alkali metal borohydrides and their application to simple reductions

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