Asymmetric synthesis of the Roche ester and its derivatives by rhodium-INDOLPHOS-catalyzed hydrogenation

(S)-3-Hydroxy-2-methylpropionate, known as the Roche ester, and several of its derivatives were successfully synthesized through asymmetric rhodium-catalyzed hydrogenation, using INDOLPHOS (diisopropyl{1-[(S)-3,5-dioxa-4-phosphacyclohepta[2,1-a;3,4-a]dinaphthalen-4-yl]-3-methyl-2-indolyl}phosphine) as the chiral ligand, in excellent yield and the highest ee reported up to now (TOF over 5500 h-1 at 25 °C; up to 98% ee at -40 °C).