Regioselective and diastereoselective phosphine-catalysed [3+2] cycloadditions to 5-methylenehydantoins: reversal of regioselectivity using chiral N-2-butynoyl-(4S)-benzyloxazolidinone
摘要:
The phosphine-catalysed [3+2] cycloaddition of 5-methylenehydantoins 1 with the ylides 2a and 2b gives spirocyclic products with reverse regioselectivities; the latter ylide gives optically active products. (C) 2002 Elsevier Science Ltd. All rights reserved.