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Enzyme catalyzed addition of hydrocyanic acid to substituted pivalaldehydes — A novel synthesis of (R)-pantolactone

1995; Elsevier BV; Volume: 6; Issue: 1 Linguagem: Inglês

10.1016/0957-4166(94)00384-n

1362-511X

Franz Effenberger, Joachim Eichhorn, Jürgen Roos,

Enzyme Production and Characterization

(R)-Cyanohydrins (R)-2b-h are obtained in good optical yields by (R)-oxynitrilase catalyzed enantioselective addition of HCN to β-substituted pivalaldehydes 1b-h. Under optimized reaction conditions with highly purified (R)-oxynitrilase, hydroxypivalaldehyde (1a) is converted to (R)-2a in satisfactory chemical and optical yields. By acid-catalyzed hydrolysis the cyanohydrins (R)-2a-h cyclize directly to give crude (R)-pantolactone (R)-3 with ee-values of 56–95% which, after recrystallization, go up to ≥98 %ee in all cases.