Intramolecular transfer of axial to central chirality in the Strecker reaction. Synthesis and stereochemistry of 5,7-dicyano-6,7-dihydro-5H-dibenz[c,e]azepines

The reaction of unsubstituted as well as 6,6'-disubstituted biphenyl-2,2'-d icarboxaldehydes with HCN and ammonia or methylamine has been investigated. It has been found mat the final reaction step, the addition of HCN to the intermediary cyclic imino nitriles, is a strictly diastereoselective proces s, yielding always only one of the two diastereoisomers of the title produc ts, the stereoselection being controlled by the chiral twist of the biaryl axis. (C) 1999 Elsevier Science Ltd. All rights reserved.