Stereochemistry of the Reactions of Cyclic Ketones with Lithium Aluminum Hydride and Methyllithium. IV. The Stereochemistry of the Reactions in 2,2‐Dimethyl‐4‐ t ‐Butylcyclohexanone Systems

Previous publication showed that the stereochemistry of lithium aluminum hydride reduction of cyclic ketones can be evaluated by the use of an empirical equation, . This paper reports further test of this relationship in the new system of 2,2‐dimethyl‐4‐ t ‐butyl‐cyclohexanone. Lithium aluminum hydride reduction of this ketone yields 95.6% trans ‐alcohol (lit., 95.9%) corresponding to D̊( D̊G *) H of 1.67 Kcal / mol . With methyllithium, the ketone formed 77.5% of trans ‐alcohol (D̊( D̊G *) D̊fs = 0.67 Kcal / mol ). These data give a calculated D̊G * = 0.74 Kcal / mol which agrees well with the literature value of 0.87 or 0.28 Kcal / mol . Structural assignments of 2,2‐dimethyl‐4‐ t ‐butylyclohexanone, 1,2,2‐trimethyl‐ cis ‐ and trans ‐4‐ t ‐butylcyclohexanols by pmr spectroscopic method are also given.