BigPatents India

A process for the preparation of a compound of Formula (1) : Formula (1) wherein: X is S, O or NR1, wherein R5 is II or an organic group; R is II or an organic group; R1 and R2 each independently are II, optionally substituted alkyl or optionally substituted aryl; G is a substituent; and n is 0 to 3: which comprises the steps: (a) reacting a compound of Formula (2) with a compound of Formula NHR1 R2 to give a compound of Formula (3): Formula (2) Formula (3) wherein X, R, G and n are as defined above and R4 is optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl or a combination thereof; and (b) reducing the compound of Formula (3) to give a compound of Formula (I) is provided. Processes for the preparation of a compounds of Formula (2), novel compounds of Formula (3) and certain preferred catalysts of formula: Formula (A) wherein: R6 represents a neutral optionally substituted hydrocarbyl, a neutral optionally substituted perhalogenated hydrocarbyl, or an optionally substituted cyclopentadienyl ligand; A represents an optionally substituted nitrogen; B represents an optionally substituted nitrogen, oxygen, sulphur or phosphorous; 1! represents a linking group; M represents a metal capable of catalysing transfer hydrogenation; and Y represents an anionic group, a basic ligand or a vacant site; provided that at least one of A or B comprises a substituted nitrogen and the substituent has at least one chiral centre; and provided that when Y is not a vacant site that at least one of A or B carries a hydrogen atom, are also provided.