Preparation of functional phosphorus zwitterions from activated alkanes, aldehydes, and tributylphosphine: synthesis of polysubstituted furo[3,2-c]coumarins.

A general preparation of new types of highly functional phosphorus zwitterions is realized via tandem three-component reactions using the corresponding functional alkanes, aldehydes, and Bu(3)P. Starting from our novel zwitterions as synthetic reagents with commercially available acid chlorides in a one-step procedure provides an attractive approach toward furo[3,2-c]coumarins.