A new manufacturing process for (S)-3-(aminomethyl)-5-methylhexanoic acid (Pregabalin), the active ingredient in Lyrica, has been developed. Using Lipolase, a commercially available lipase, rac-2-carboxyethyl-3-cyano-5-methylhexanoic acid ethyl ester (1) can be resolved to form 2-carboxyethyl-3-cyano-5-methylhexanoic acid (2). A heat-promoted decarboxylation of 2 efficiently generates (S)-3-cyano-5-methylhexanoic acid ethyl ester (3), a known precursor of Pregabalin. This new route dramatically improved process efficiency compared to the first-generation process by setting the stereocenter early in the synthesis and enabling the facile racemization and reuse of (R)-1. The chemoenzymatic process also reduced organic solvent usage resulting in a mostly aqueous process. Compared to the first-generation manufacturing process, the new process resulted in higher yields of pregabalin (40-45% after one recycle of (R)-1), and substantial reductions of waste streams corresponding to a 5-fold decrease in the E factor from 86 to 17.

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Monosubstituted phosphinic acids are esterified with orthosilicates in excellent yields. Phosphinylidene-containing acids react selectively under these conditions, while disubstituted phosphinic acids and phosphonic acids remain unchanged. One-pot procedures are also described for the preparation of phosphinate esters from an alcohol. This novel method provides a convenient and general alternative to more commonly employed conditions such as diazomethane or carbodiimide.

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Highly efficient stereoselective syntheses of both (Z)-and (E)-γ-bisabolenes (1) were achieved by ring closing metathesis of stereodefined tetrasubstituted alkenes. Both (Z)-and (E)-tetrasubstituted alkene precursors were obtained by Cu-catalyzed stereoselective addition of allylmagnesium