(+)-Exo-brevicomin via an organometallic boulevard
摘要:
The brevicomin carbon skeleton was efficiently constructed through a novel 2 + 3 + 4 sequence via organocuprate and Suzuki couplings. The Sharpless catalytic asymmetric dihydroxylation provided either naturally occurring (+)-exo-brevicomin (+)-7 or its enantiomer, (-)-7, both in 95% ee, in 61% overall yield from allyl bromide.
Optically pure (+)-endo- and (+)-exo-brevicomin have been synthesized in short steps starting from α-hydroxy ketone derivative, (R)-4-benzyloxy-8-nonen-3-one (3), which was prepared via enzymatichydrolysis of racemic enolester 4..