Preparation of (2E,4E,6S,7S,10E,12E,14S,15S,1′S)‐7,15‐Bis(1′‐hydroxymethylethyl)‐6,14‐dimethyl‐8,16‐dioxa‐2,4,10,12‐cyclohexadecatetraene‐1,9‐dione. – A Building Block for the Synthesis of Elaiophylin

Abstract

AbstractThe title compound 2, which is considered to be a possible key intermediate for a synthesis of the antibiotic elaiophylin (1), has been obtained by cyclodimerisation of the hydroxy acids 18 and 27 using Yamaguchi's method. The hydroxy acids 18 and 27 are synthesised by Wittig reaction of the (phosphoranylidene)crotonate 14 with the protected 3,5‐dihydroxy‐2,4‐dimethylpentanals 12 and 23, respectively. These are constructed, in turn, by diastereoselective Evans aldol reaction between (S)‐3‐benzyloxy‐2‐methylpropanal (4) and (R)‐4‐isopropyl‐3‐propionyl‐2‐oxazolidionne.