Enantioselective Addition of Allyltrichlorosilane to Bulky-substituted Aldehydes Catalyzed by Axial N , N′ -Dioxide Pivalate

Allylation of bulky-substituted aromatic aldehydes with allyltrichlorosilanes were catalyzed by axial biscarboline N , N’ -dioxide esters with high enantioselectivities up to 92% e.e. for 1-(4-chlorophenyl)-9-methyl-9H-pyrido[3,4- b ]indole-3-carbaldehyde and 90% e.e. for 1-(3-methoxyphenyl)-9-methyl-9 H -pyrido[3,4- b ]indole-3-carbaldehyde, respectively. Total 22 aldehydes were tested with good yields and enantioselectivities. Catalyst 4 f exhibited good catalytic enantioselectivity.