Microwave-assisted synthesis and diels–alder reactions of 1,3-azaphospholo[5,1-a]isoquinolines

✍ Scribed by Raj K. Bansal; Anshu Dandia; Nidhi Gupta; Dheeraj Jain

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 76 KB
• Volume: 14
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/hc.10193

✦ Synopsis

Abstract

The application of microwave technique has been extended successfully for the first time to the synthesis of a representative class of azaphospholes, viz. 1,3‐bis(alkoxycarbonyl)‐1,3‐azaphospholo[5,1‐a]isoquinolines (2), which occurs rapidly giving higher yields. Stereoselectivity is observed in the reaction with 2,3‐dimethyl‐1,3‐butadiene, and isoprene reacts regioselectively as well. 1‐Methyl‐3‐ethoxycarbonyl‐1,3‐azaphospholo[1,5‐a]pyridine (4) remains inert toward [2+4] cycloaddition. The nonoccurrence of the Diels–Alder reaction in the latter case has been supported by semiempirical PM3 calculations. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:560–563, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10193