Stereoselective alkylation of alpha,beta-unsaturated imines via C-H bond activation.
The stereoselective alkylation of alpha,beta-unsaturated imines via C-H activation followed by imine hydrolysis produces tri- and tetrasubstituted alpha,beta-unsaturated aldehydes. In the presence of a rhodium catalyst, alpha,beta-unsaturated N-benzyl imines derived from methacrolein, crotonaldehyde, and tiglic aldehyde undergo directed C-H activation at the beta-position and react with terminal alkenes and alkynes to form the tri- and tetrasubstituted alpha,beta-unsaturated imines with very high stereoselectivity. Hydrolysis to provide alpha,beta-unsaturated aldehydes can be performed under carefully controlled conditions that maintain the stereochemistry of the beta-alkylated imine products. Alternatively, for beta-alkylation products of the N-benzyl imine of methacrolein, hydrolysis can be performed under conditions that provide complete isomerization to the E isomer.
Colby
Denise A
DA
Department of Chemistry, University of California, and Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Bergman
Robert G
RG
Ellman
Jonathan A
JA
D000478:Alkylation; D002244:Carbon / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D013237:Stereoisomerism
D002244:Carbon; D006859:Hydrogen