Enantioselective synthesis of planar-chiral carba-paracyclophanes: Rhodium-catalyzed [2+2+2] cycloaddition of cyclic diynes with terminal monoynes

Abstract

Just 'plane' chiral: The high-yielding and highly enantioselective synthesis of carba[10]-[12]paracyclophanes has been achieved with up to 91 % yield and 93 %ee by using the cationic rhodium(I)/(S,S)-bdpp-catalyzed [2+2+2] cycloaddition of cyclic diynes with terminal monoynes under high substrate concentrations. nbd=2,5-norbornadiene, Ns=p-nitrobenzenesulfonyl, Ts=4-toluenesulfonyl. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.