From highly enantioselective catalytic reaction of 1,3-diynes with aldehydes to facile asymmetric synthesis of polycyclic compounds

J Am Chem Soc. 2011 Aug 3;133(30):11780-94. doi: 10.1021/ja204289q. Epub 2011 Jul 11.

Abstract

(S)-1,1'-Binaphth-2-ol (BINOL) in combination with ZnEt(2), Ti(O(i)Pr)(4), and biscyclohexylamine was found to catalyze the highly enantioselective (83-95% ee) addition of various 1,3-diynes to aldehydes of diverse structures. This method provides a convenient pathway to generate a number of optically active dienediynes as the acyclic precursors to polycyclic compounds. The chiral dienediynes undergo highly chemoselective Pauson-Khand (PK) cycloaddition in benzaldehyde by using [Rh(cod)Cl](2) as the catalyst in the presence of rac-BINAP. High diastereoselectivity (up to >20:1) has also been achieved with the chiral dienediyne substrates containing a bulky substituent adjacent to the chiral center. In the presence of the Grubbs II catalyst, ring-closing enyne metathesis of the PK cycloaddition products led to the formation of the desired 5,5,7- and 5,5,8-fused tricyclic compounds. Further highly diastereoselective Diels-Alder reaction of a 5,5,7-tricyclic compound with maleic anhydride produced a 5,5,7,6-polycyclic product. The asymmetric synthesis of polycyclic compounds from optically active dienediynes has established a novel and efficient synthetic route to the structural framework of many biologically significant molecules.

Publication types

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

MeSH terms

  • Aldehydes / chemistry*
  • Catalysis
  • Cyclization
  • Diynes / chemistry*
  • Molecular Structure
  • Polycyclic Compounds / chemical synthesis*
  • Polycyclic Compounds / chemistry
  • Stereoisomerism

Substances

  • Aldehydes
  • Diynes
  • Polycyclic Compounds