Understanding the origins of remote asymmetric induction in the boron aldol reactions of beta-alkoxy methyl ketones.
We report theoretical studies into the remote 1,5-stereoinduction shown by certain types of beta-alkoxy methyl ketones in boron-mediated aldol reactions with achiral aldehydes. For a range of common alkoxy groups, our calculations are in excellent agreement with experimentally observed diastereoselectivities. In the aldol transition structures, a stabilizing hydrogen bond between the alkoxy oxygen and formyl proton leads to preferential formation of the 1,5-adduct, by minimizing steric interactions between the beta-alkyl group and one of the ligands on boron.
Paton
Robert S
RS
Unilever Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
Goodman
Jonathan M
JM
D001895:Boron / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular
D007659:Ketones; D001895:Boron