Total Synthesis of (-)-Lundurine A and Determination of its Absolute Configuration

摘要

A 15-step total synthesis of (-)-lundurine A (1) from easily accessible (S)-pyrrolidinone 18 is reported. A Simmons-Smith reaction allows the efficient, simultaneous assembly of the cyclopropyl C ring, the six-membered D ring, the seven-membered E ring, and the quaternary carbon stereocenters at C2 and C7. The absolute configuration of natural (-)-lundurine A was deduced to be 2R,7R,20R based on the stepwise construction of the stereocenters during the total synthesis.