DIASTEREO- AND ENANTIOSELECTIVE INTRAMOLECULAR 1,6-C-H INSERTION REACTION OF DIARYLDIAZOMETHANES CATALYZED BY CHIRAL DIRHODIUM(II) CARBOXYLATES

A highly diastereo- and enantioselective intramolecular 1,6-C-H insertion reaction of diaryldiazomethanes possessing an ether group has been achieved with the use of dirhodium(II) tetrakis[N-phthaloyl-(S)-tert-leucinate] as a catalyst, providing exclusively 3-substituted cis-3,4-dihydro-4-phenyl-1H-isochromans in up to 99% ee with no evidence of tandem ylide formation-rearrangement.