Process and intermediate compounds useful in the preparation of statins, particularly atorvastatin

Abstract

There is provided a process for the preparation of a compound of formula (7) or salts thereof: wherein Rrepresents a hydrogen or a hydrocarbyl group, Rrepresents a hydrogen or substituent group, Rrepresents a hydrogen or a hydrocarbyl group, and X represents a hydrogen or substituent group which comprises a) cyanating a compound of formula (1): wherein Y represents a halo group, preferably CI or Br; Prepresents hydrogen or a protecting group, and W represents =0 or —OP, in which Prepresents hydrogen or a protecting group, to give a compound of formula (2): b) reducing the compound of formula (2) to give a compound of formula (3): coupling the compound of formula (3) with a compound of formula (4): to give a compound of formula (5): when W represents —OP, deprotecting and then oxidising the compound of formula (5) to give a compound of formula (6): and e) subjecting the compound of formula (5) when W represents ═O, or compound of formula (6) to ring-opening, and removal of any remaining protecting groups, to give a compound of formula (7) or salts thereof