Transfer hydrogenation process and catalyst

A ligand having the following formula:

• in which:
• W represents —OH or —NH2;
• R32 represents an aryl group having at least one —SO3H or —S3M1 substituent wherein M1 is an alkali metal and is further optionally substituted;
• and
• R33, R34 are independentiy optionally substituted hydrocarbyl groups or R33 and R34 are optionally linked in such a way as to define an optionally substituted ring.

A process comprising reacting a di-sulphide of formula:

• with an oxidant to produce a compound of formula:
• wherein:
• W is —OH or —N H2;
• R32 is an aryl group having at least one —SO3H or SO3M1 (M1 =alkali metal) substituent;
• R35 is an aryl group;
• and
• R33, R34 are independently optionally substituted hydrocarbyl groups or R33 and R34 are optionally linked in such a way as to define an optionally substituted ring.

A process for the transfer hydrogenation of an organic compound having a carbon-carbon or carbon-heteroatom double bond,

• said process comprising reacting the organic compound with a hydrogen donor in the presence of a catalyst having the general formula:
• in which:
• R18 represents an optionally substituted hydrocarbyl or perhalogenated hydrocarbyl ligand;
• A represents —NR19—, —NR20, —NHR19, —NR19R20 or —NR20R21 where R19 is H, C(O)R21, SO2R21, C(O)NR21R25, C(S)NR21R25, C(═NR25)SR26 or C(═NR25)OR26, R20 and R21 each independently represents an optionally substituted hydrocarbyl, perhalogenated hydrocarbyl or an optionally substituted heterocyclyl group, and R25 and R26 are each independently hydrogen or a group as defined for R21;
• B represents —O—, —OH, OR22, —S—, —SH, SR22, —NR22—, —NR23—, —NHR23, —NR22R23, —NR22R24, —PR22— or —PR22R24 where R23 is H, C(O)R24, SO2R24, C(O)NR24R27, C(S)NR24R27, C(═NR27)SR28 or C(═NR27)OR28, R22 and R24 each independently represents an optionally substituted hydrocarbyl, perhalogenated hydrocarbyl or an optionally substituted heterocyclyl group, and R27 and R28 are each independently hydrogen or a group as defined for R24;
• E 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 when Y is not a vacant site that at least one of A or B carries a hydrogen atom,
• characterised in that at least one of said groups R20 to R22 or R24 to R28 is present in the form of an optionally substituted suiphonated hydrocarbyl group, a sulphonated perhalogenated hydrocarbyl group, or an optionally substituted sulphonated heterocyclyl group.