GRIGNARD REAGENT INDUCED SELF-CONDENSATION OF BENZOXAZOLES: SYNTHESIS OF BENZOXAZOLYLALKYL ALKYL KETONES.
2-Alkylbenzoxazoles 1 undergo clean Claisen-type self-condensation upon treatment with n-BuMgBr and quenching with aqueous NH4Cl to give 5.In contrast, quenching of the reaction with aqueous HCl furnishes quite good yields of the benzoxazolylalkyl alkyl ketones 8.