A New Synthetic Application of 1,2-Benzodithiolium Cations: Synthesis of Aldehydes by 1-Carbon Homologation of Carbonyl Compounds

Article abstract of DOI:10.1055/s-1987-27857

Eleven aldehydes (6a-l) were synthesized by 1-carbon homologation of ketones and aldehydes according to the following sequence: Horner-Emmons reaction of 2-(O,O-dimethylphosphonyl)-1,3-benzodithiole (1) and various carbonyl compounds (2) to give benzo-1,4-dithiafulvenes (3); reduction with sodium borohydride and tetrafluoroboric acid-ether complex in dry acetonitrile to 1,3-benzodithioles (5); subsequent hydrolysis of these with mercury(II)oxide and aqueous tetrafluoroboric acid (35percent) in tetrahydrofuran.The procedure is simple, of wide application, and afforded pure aldehydes in good overall yields (55-88percent).