(R)-(+)-t-Butyl 2-(p-Tolylsulfinyl)propionate


[83909-72-2]  · C14H20O3S  · (R)-(+)-t-Butyl 2-(p-Tolylsulfinyl)propionate  · (MW 268.37) (R,S)


(reagent for asymmetric aldol-type condensation)

Physical Data: [a]D = +148° (EtOH, c = 0.3) for the 1:1 mixture of diastereomers.

Preparative Methods: the synthesis of this compound was first reported by methylation of (R)-(+)-t-Butyl 2-(p-Tolylsulfinyl)acetate via enolate generation with lithium bases such as n-Butyllithium or t-Butyllithium at 0 °C and with only Iodomethane as the alkylating agent (eq 1).1 The diastereomeric ratio was shown by 1H NMR to be 50:50 with BuLi and 42:58 with t-BuLi. The title compound was also prepared from (-)-(1R,2S,5R)-Menthyl (S)-p-Toluenesulfinate and the magnesium enolate of t-butyl propionate in 68% yield as a 1:1 ratio of the two possible diastereomers (eq 2).1

Aldol-Type Condensation.

The aldol-type condensation of the enolate anion of sulfinylpropionate, which was prepared as usual with the base t-butylmagnesium bromide, with aldehydes afforded after desulfurization with Aluminum Amalgam the corresponding b-hydroxy esters in high yield (90%) and, with aliphatic aldehydes, high diastereoselectivity (eq 3).2,3 The amount of asymmetric induction was determined by transformation of the b-hydroxy esters to the corresponding isopropyl-substituted alcohols.

1. Solladié, G.; Matloubi-Moghadam, F.; Luttmann, C.; Mioskowski, C. HCA 1982, 65, 1602.
2. Solladié, G.; Mioskowski, C. T 1980, 36, 227.
3. Solladié, G. S 1981, 185.

Guy Solladié & Françoise Colobert

University Louis Pasteur, Strasbourg, France

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