Total Synthesis of (+)- epi-Condyfoline

Org Lett. 2019 Dec 6;21(23):9594-9597. doi: 10.1021/acs.orglett.9b03762. Epub 2019 Nov 18.

Abstract

Herein, we report the first asymmetric total synthesis of aspidospermatan indole alkaloid (+)-epi-condyfoline (1) in 15 steps from commercially available 2-methylindole-3-carboxaldehyde. Key steps include (1) our domino Michael/Mannich annulation method of N-sulfinyl metallodienamines to set three contiguous stereocenters, (2) LiHMDS-mediated cyclization of an ω-tosyloxy N-sulfinamide to prepare the signature indole-fused 2-azabicyclo[3.3.1]nonane framework, and (3) DMTSF-promoted spirocyclization of a dithioacetal intermediate to access the final pyrrolidine ring. Functional group manipulations delivered the targeted alkaloid (+)-epi-condyfoline (1) in 13 steps and 1.25% overall yield from N-sulfinylimine (+)-8.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.