Enantio- and diastereoselective synthesis of highly substituted benzazepines by a multicomponent strategy coupled with organocatalytic and enzymatic procedures.

ABSTRACT

Enantiomerically pure 4,5-dihydro-1H-benzo[c]azepines with three contiguous stereogenic centers have been assembled by convergent strategy with a good control of diastereoselectivity. The two steps are as follows an asymmetric organocatalytic Mannich reaction performed on Boc-imines of o-(azidomethyl)benzaldehydes, followed by a one-pot Staudinger/aza-Wittig/Ugi-Joullié sequence. The latter reaction represents one of the first examples of diastereoselective Ugi three-component reaction on a seven-membered cyclic imine. The o-azidomethylbenzaldehydes have been synthesized employing a simple and efficient chemoenzymatic strategy from commercially available building blocks.