Ethenylbenzothiazoles were synthesized by the Horner-Emmons reaction of benzothiazolylmethylphosphonate with aldehydes under phase transfer catalytic conditions in 60-71% yields. Not only aromatic but also aliphatic aldehydes gave the desired products under these mild conditions in 66-71% yields.
Benzothiazolylchloromethyllithium 1c and benzothiazolyldichloromethyllithium 1e, easily available by lithiation of 1b and 1d (or 1f) respectively, undergo a different type of self-condensation reaction giving 5 and 7a respectively. The possibility that 1c and 1e behave as halocarbenoids is discussed.
Ethenylbenzothiazoles were synthesized by the Horner-Emmons reaction of benzothiazolylmethylphosphonate with aldehydes under phase transfer catalytic conditions in 60-71% yields. Not only aromatic but also aliphatic aldehydes gave the desired products under these mild conditions in 66-71% yields.