Atropisomers of arylmaleimides: stereodynamics and absolute configuration

J Org Chem. 2013 Apr 19;78(8):3709-19. doi: 10.1021/jo400200v. Epub 2013 Apr 8.

Abstract

4-Aryl-3-bromo-N-benzylmaleimides and 3,4-biaryl-N-benzylmaleimides have been synthesized by a modified Suzuki cross-coupling reaction from 3,4-dibromo-N-benzylmaleimide. The conformational studies by dynamic NMR and DFT calculations showed that the interconversion barrier between the two available skewed conformations is under steric control. When the aryl group was a 2-methylnaphthyl, thermally stable atropisomers were isolated by enantioselective HPLC and their absolute configurations were assigned by TD-DFT simulations of the ECD spectra.