An efficient Amano PS-catalyzed chemo-, regio- and enantioselective hydrolysis of (±)-2,3-di-O-acetyl-2-C-methyl-d-erythrono-1,4-lactone: a facile preparation of bioactive natural products (−)-saccharinic acid lactone and potassium (2R,3R)-2,3,4-trihydrox

Saccharinic acid lactone (−)-1a is a suitable building block for the synthesis of many bioactive natural products. Amano PS-induced chemo-, regio- and enantioselective hydrolysis of diacetyl lactone (±)-3 has been carried out to obtain (−)-1a in 46% yield with 99% ee and diacetyl lactone (+)-3 in 49% yield with 99% ee. The Amano PS-catalyzed enantioselective acylation of (±)-1a with vinyl acetate as an acyl donor was relatively less efficient and furnished (−)-7 in 31% yield with 99% ee and (+)-1a in 63% yield. The conversion of (−)-1a to leaf-closing substance 2a and an attempted approach to naturally occurring compounds 1b and 2b have been also described.

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(+)-(2S,3S)-2,3-Di-O-acetyl-2-C-methyl-d-erythrono-1,4-lactoneC9H12O6Ee = 99%[α]D20=+9.0 (c 1.6, CHCl3)Source of chirality: enzyme ‘Amano PS’Absolute configuration: 2S,3S

(−)-(3R,4R)-3,4-Dihydroxy-3-methyldihydrofuran-2-oneC5H8O4Ee = 99%[α]D20=-58.6 (c 0.50, H2O)Source of chirality: enzyme ‘Amano PS’Absolute configuration: 3R,4R

(−)-(3R,4R)-Acetic acid 4-hydroxy-4-methyl-5-oxotetrahydrofuran-3-yl esterC7H10O5Ee = 99%[α]D20=-44.0 (c 0.20, CHCl3)Source of chirality: enzyme ‘Amano PS’Absolute configuration: 3R,4R