1,3-versus 1,2-Asymmetric induction in the reduction of β-hydroxy ketones by intramolecular hydrosilylation

Abstract

The role of 1,2-asymmetric induction has been investigated in the 1,3-anti-selective reduction of β-hydroxy ketones via intramolecular hydrosilylation. For the α-methyl β-hydroxy ketones 2a, 3a, the effect of the α-substituent is negligible except that it appears to reinforce 1,3-asymmetric induction. For the α-ethyl β-hydroxy ketones 2b, 3b, 1,3-asymmetric induction is dominant but not overwhelming. The super-acid TfOH₂⁺ B(OTf)₄^– has been used as a catalyst for the hydrosilylation giving, in one case, an improved result when compared with previous methodology.