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.