Enantioselektive Verseifungen substituierter, achiraler 3‐Acyloxy‐propylester mit Lipasen: Herstellung chiraler Derivate von „Tris(hydroxymethyl)methan”︁

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Abstract
Enantioselective Saponification of Substituted, Achiral 3‐Acyloxy‐propionates with Lipases: Synthesis of Chiral Derivatives of „Tris(hydroxymethyl)methane”︁Ethyl 3‐hydroxy‐2‐(hydroxymethyl)propionate (11) was synthesized with an overall yield of 40% starting from the pentaerythritol derivative 5,5‐bis(hydroxymethyl)‐1,3‐dioxane (7). Both OH groups of 11 were acylated (ethanoyl‐, propanoyl‐, butanoyl, hexanoyl, and octanoyl derivatives 6a—e), and the formed triesters were partially hydrolyzed by lipases. According to 19F‐NMR analysis of the corresponding Mosher ersters, the monocapronate 12d formed by PPL (porcine pancreas lipase) showed an enantiomeric ratio of 93.5:6.5 (87% ee). Using standard reactions, it was converted into chiral non‐racemic derivatives 16 (O‐benzyl‐O′‐silyl) and 21 (O‐benzyl‐O′‐methoxymethyl) of the C3v‐symmetric title compound. Possible applications of these derivatives are discussed. A “model” for the enantioselectivity of PPL hydrolysis is formulated.