Methods for the preparation of thiazolidinethione indene-based chiral auxiliaries

Methods for the preparation of indene-based thiazolidinethiones are provided comprising contacting 1-amino-2,3-dihydro-1H-inden-2-ol, or a substituted derivative thereof, with an acid under suitable reaction conditions to provide a first intermediate; and contacting the first intermediate with an alkali xanthate in the presence of an alkali hydroxide under suitable reaction conditions to provide a compound of formula (III), wherein R1-R8 are defined herein.