556. Reductions with aluminium alkoxides. Part I. The relative proportion of epimers in alcohols derived from cyclic ketones

Abstract

2641 556. Reductions with Aluminium Alkoxides. Part I. The Relative Proportion of Epirners in Alcohols derived from Cyclic Ketones.

Recent Developments In Meerwein−Ponndorf−Verley and Related Reactions for the Reduction of Organic Functional Groups Using Aluminum, Boron, and Other Metal Reagents: A Review

“…The generally accepted mechanism for MPV reactions proceeds via a complex in which both the carbonyl compound and the reducing alcohol are bound to the metal ion, as shown in Scheme for the reaction of aluminum isopropoxide. The carbonyl is then activated upon coordination to Al(III), followed by a hydride transfer from the alcoholate to the carbonyl group via a six-membered transition state 1 …”

The Stereoisomerism of Cyclohexane Derivatives.

“…Chromic acid oxidation of ( -)-menthol yields ( -)-menthone, whereas reduction of the latter provides a mixture of (+)-neomenthol (70 per cent) and ( -)menthol (30 per cent) (99). The reduction of menthone to neomenthol by the Ponndorf method has been investigated recently (148). Using the aluminum alkoxides of sterically hindered secondary alcohols, such as methyl-tert-butylcarbinol, even higher yields of neomenthol have been realized than those (70 per cent) obtained with aluminum isopropoxide.…”

Stereochemistry of Reduction of Ketones by Complex Metal Hydrides

“…The pyridine was removed in vacuum and the isobor~leol (106 mg), m.p. 210" from petroleum ether, separated by steam distillation (23 (24). The isolated product therefore contains 15% (from nko) or 17% ((from diO) of the cis-isomer.…”