Chirality transfer in the synthesis of 2,3-dihydro-1,4-dithiine derivatives

A new method for the synthesis of chiral 2,3-dihydro-1,4-dithiine derivatives that involves a reaction of chiral cyclic aliphatic dithioacetal in the presence of Lewis acid has been developed. The title product contains a 1,4-dithiane substituent with two stereogenic centers. The presence of a stereogenic center in the alpha position to the cyclic dithioacetal substrate controls the stereogenicity of two centers in the newly formed molecule whose absolute configuration is defined. The mechanism based on chirality transfer process was proposed.