Total Synthesis of (−)-Citreoisocoumarin, (−)-Citreoisocoumarinol, (−)-12-epi-Citreoisocoumarinol, and (−)-Mucorisocoumarins A and B Using a Gold(I)-Catalyzed Cyclization Strategy

A unified and concise first asymmetric total synthesis of (−)-citreoisocoumarin (2), (−)-citreoisocoumarinol (3), 12-epi-citreoisocoumarinol (4), and (−)-mucorisocoumarins A (5) and B (6) have been accomplished from the common intermediate (−)-6-O-methyl-citreoisocoumarin (1). Central to the synthetic approach is a regioselective gold(I)-catalyzed 6-endo-dig cyclization strategy for the construction of the isocoumarin skeleton. The other key...