Enantioselective synthesis of chiral 1,2-diamines by the catalytic ring opening of azabenzonorbornadienes: application in the preparation of new chiral ligands

In the presence of a rhodium catalyst (5 mol %) generated in situ from [Rh(cod)C]12 and (S,S')-(R,R')-C-2-ferriphos-tolyl, the asymmetric ring-opening reaction of N-Boc-azabenzonorbornadienes with dibenzylamine proceeded with excellent enantioselectivity (up to > 99% ee) to give the corresponding 1,2-diamine scaffolds in high yields. The sequential deprotection of the ring-opened products and treatment with tartaric acid gave the enantiomerically pure 1.2-diamine tartrate salts. These salts were used for the preparation of new chiral ligands Such as the salen-type ligands and Trost-type ligands, (c) 2006 Elsevier Ltd. All rights reserved.