Abstract An efficient route to 2′, 3′-dihydro-2′-thioxospiro [indole-3, 6′-[1, 3] thiazin]-2 (1H)-one derivatives is described. It involves the reaction of isatine, 1-phenyl-2-(1, 1, 1- triphenyl-λ 5-phosphanylidene) ethan-1-one, and different amines in the presence of CS 2 in dry MeOH at reflux (Scheme 1). The alkyl carbamodithioate, which results from the addition of the amine to CS 2, is added to the α, β-unsaturated ketone, resulting from the reaction ...