Stereochemistry of nucleophilic reductions of 2-methyl-4-t-butylcyclohexanones. Further support for the linear combination of SSC and PSC stereochemical models
Resource
Journal of the Chemical Society, Perkin Transactions 2, 1989: 747-750
Journal
Journal of the Chemical Society, Perkin Transactions 2
Journal Issue
7
Pages
747-750
Date Issued
1989
Author(s)
Abstract
Trans-2-Methyl-4-t-butylcyclohexanone reacts with lithium aluminum hydride, lithium trimethoxyaluminium hydride and methyl-lithium with equal stereoselectivity of axial attack (i.e. 95 ± 1%). This is attributed to the equal steric strain control (SSC) of these three reagents in the absence of product stability control (PSC) brought about by the equal stability of its two secondary alcohol products (i.e. ΔG°= 0 and Δπ=aΔG°= 0). Also presented for comparison are the stereochemistries of the reactions of 4-t-butylcyclohexanone, 2-methylcyclohexanone, cis-2-methyl-4-t-butylcyclohexanone and 2,2-dimethyl-4-t-butylcyclohexanone. In these three systems, the stereochemical courses of addition are controlled by SSC(Δδ) and PSC(Δπ) simultaneously, i.e. Δ(ΔG‡)=Δδ+Δπ. © 1989 by The Royal Society of Chemistry.
Type
journal article