Herstellung enantiomerenreiner Derivate von 3‐Amino‐ und 3‐Mercaptobuttersäure durch S N 2‐Ringöffnung des β‐Lactons und eines 1,3‐Dixoanons aus der 3‐Hydroxybuttersä ure

Preparation of Enantiomerically Pure Derivatives of 3‐Amino‐ and 3‐Mercaptobutanoic Acid by S N 2 Ring Opening of the β‐Lactone and a 1,3‐Dioxanone Derived from 3‐Hydroxybutanoic Acid From ( S )‐4‐methyloxetan‐2‐one ( 1 ), the β‐butyrolactone readily available from the biopolymer ( R )‐polyhydroxybutyrate (PHB) and various C, N, O and S nucleophiles, the following compounds are prepared:( s )‐2‐hydroxy‐4‐octanone ( 3 ), ( R )‐3‐aminobutanoic acid ( 7 ) and its N ‐benzyl derivative 5 , ( R )‐3‐azidobutanoic acid ( 6 ) ( R )‐3‐mercaptobutanoic acid ( 10 ), ( R )‐3‐(phenylthio)butanoic acid ( 8 ) and its sulfoxide 9 . The ( 6R )‐2,6‐dimethyl‐2‐ethoxy‐1,3‐dioxan‐4‐one ( 4 ) from ( R )‐3‐hydroxybutanoic acid undergoes S N 2 ring opening with benzylamine to give the N ‐benzyl derivative ( ent ‐ 5 ) of ( S )‐3‐aminobutanoic acid in 30‒40% yield.