SITE-SELECTIVE RHODIUM(II) ACETATE MEDIATED INTRAMOLECULAR METAL-CARBENE INSERTIONS INTO C-H BONDS OF BICYCLO[2.2.1]HEPTANES - EFFICIENT SYNTHESES OF (+)-ALBENE AND (-)-BETA-SANTALENE

Treatment of alpha-diazo ketones 1a-d and 2a-d with catalytic amounts of rhodium(II) acetate led to selective carbene insertions into C-H bonds resulting in cyclopentane-annulated products in high yields. The highly selective insertion realized into the exo-methyl C-H bond of 1a has been utilized in the syntheses of (+)-albene (8) and (-)-beta-santalene (11).