Origins of 1,6-stereoinduction in torquoselective 6π electrocyclizations

J Am Chem Soc. 2013 Mar 27;135(12):4878-83. doi: 10.1021/ja400882y. Epub 2013 Mar 18.

Abstract

A novel stereoselective electrocyclization developed for the total synthesis of reserpine has been explored by both experiment and theory. A stereocenter six atoms away from the newly forming chiral center is responsible for the diastereoselectivity of the ring closure. This stereogenic center, lying at the junction of two six-membered rings, defines the conformation of the substrates' fused ring skeleton that ultimately distinguishes between the two allowed, disrotatory triene geometries at the transition state. The presence of allylic strain in the disfavored transition state results in a torquoselective ring closure (dr up to 15.7:1).

Publication types

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

MeSH terms

  • Antihypertensive Agents / chemical synthesis*
  • Cyclization
  • Electrons
  • Models, Molecular
  • Reserpine / chemical synthesis*
  • Stereoisomerism

Substances

  • Antihypertensive Agents
  • Reserpine