Reactivity of functionalized N,S-ketene acetal: regioselective construction of tetrahydrobenzo[b]pyran and chromeno[2,3-b]quinoline derivatives

J Org Chem. 2010 Dec 17;75(24):8522-32. doi: 10.1021/jo101902z. Epub 2010 Nov 18.

Abstract

Regioselective synthesis of functionalized tetrahydrobenzo[b]pyrans has been developed by multicomponent reactions (MCRs) and tandem [3 + 3] annulations of β-benzoylthioacetanilides or β-(2-haloaroyl)thioacetanilides as valuable sources with aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione catalyzed by triethylamine. This MCR followed by a postcondensation cyclization via an intramolecular S(N)Ar in the presence of K(2)CO(3) led to an unprecedented novel chromeno[2,3-b]quinoline framework containing an important chromene moiety in good yields. The reactions were very mild, convenient, and o-selective to form new fused tetracyclic target molecules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetals / chemistry*
  • Benzopyrans / chemical synthesis*
  • Benzopyrans / chemistry*
  • Catalysis
  • Cyclization
  • Ethylenes / chemistry*
  • Ketones / chemistry*
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Quinolines / chemical synthesis*
  • Quinolines / chemistry*
  • Stereoisomerism

Substances

  • Acetals
  • Benzopyrans
  • Ethylenes
  • Ketones
  • Quinolines
  • ketene