[frankenstein18]

In the reduction of 4-tercbutyl-ciclohexanone, why is trans-4-terc- butilcyclohexanol the major product?

i first thought of steric hindrance but then i though of the carbocation but i dont think thats it since im not studying sn2 and sn1 reactions right now

[beardy]

Are you familiar with chair conformations? t-butyl is bulky so it remains in the equatorial position to prevent 1,3-diaxial interactions. the carbonyl is sp2 hybridized, therefore planar, so it can be attacked from top or bottom. If it's attacked from top, the -OH goes into the equatorial position. if it's attacked from the bottom, it goes into axial position. equatorial position is preferred because it doesn't have 1,3-diaxial interactions. either way, t-butyl is locked in one particular position, equatorial.