Fast [3+2] Cycloaddition Synthesis of (±) Pterocarpans under Microwave Irradiation

Herein we describe a method for the fast cycloaddition reaction of 2H-chromenes with 2-methoxy-1,4- benzoquinones by microwave heating. Using this methodology we have synthesised seven pterocarpans derivatives, five of which are novel compounds. Microwave heating allows significant yield enhancements and reduction of reaction time when compared to traditional methodology.