Rotational features of carbon-nitrogen bonds in N-aryl maleimides. Atroposelective reactions of o-tert-butylphenylmaleimides

Article abstract of DOI:10.1016/S0040-4020(99)00237-9

Atroposelective addition and cycloaddition reactions of N-2- (tertbutylphenyl)- and N-2,5 (di-tert-butylphenyl)maleimide and a substituted derivative have been studied. Good to excellent stereoselectivities are generally observed, and high rotation barriers (about 29 kcal/mol) prevent the products from inter, converting. Crystal structures of the precursors and products support a straightforward model where reactants attack trans to the o-tert butyl group.