Carbanions derived from 2-alkylthiobenzothiazoles. A novel α-lithiomethyl mercaptan synthon for mercaptomethylation

2-Methylthiobenzothiazole readily gives a methyl group lithio derivative which reacts cleanly with electrophiles. The products are conveniently converted into the corresponding thiols by BuLi at –78 °C, and this sequence thus provides a convenient two-step mercaptomethylation procedure for alkyl halides, aldehydes, and ketones.