3,4-DIHYDROISOCOUMARINS FROM ALPHA-BROMO-O-TOLUNITRILE AND KETONES ORALDEHYDES

o-Cyanobenzyllithium (3) was efficiently generated by lithium-telurium exchange of the corresponding benzylic telluride 2 prepared in situ f rom lithium butanetellurolate and alpha-bromo-o-tolunitrile (1). React ion of ketones or aldehydes with 3 afforded substituted 2-hydroxyethyl benzonitriles 4 in high yields. The subsequent acid-catalyzed lactoniz ation gave 3-substituted 3,4-dihydroisocoumarins 5 in good yields. All these successive reactions could be performed in the same reaction fl ask without isolation of intermediates.