Ruthenium complexes and their uses as catalysts in processes for formation and/or hydrogenation of esters, amides and related reactions

A process for preparing an amino acid or a salt thereof by contacting an amino alcohol with a Ruthenium complex as a catalyst, in the presence of water and a base, under conditions sufficient to generate the amino acid or a salt thereof, wherein the Ruthenium complex is selected from the group consisting of:

• (i) a complex of Formula A11′, A22′ or A33′:
• wherein
• L1 and L2 are each independently selected from the group consisting of nucleophilic carbene (:C(R)2), P(R)2, P(OR)2, N(R)2, imine, SR, SH, S(═O)R, heteroaryl wherein the heteroatom is selected from nitrogen and sulfur, As(R)2, Sb(R)2 and an N-heretocyclic carbene represented by the structure:
• each of R, R2 and R3 are independently selected from the group consisting of alkyl, cycloalkyl, aryl, alkylaryl, heterocyclyl and heteroaryl;
• L3 is a mono-dentate two-electron donor selected from the group consisting of CO, P(R)3, P(OR)3, NO+, As(R)3, Sb(R)3, S(R)2, nitrile (RCN) and isonitrile (RNC) wherein R is as defined above;
• L4 is absent or is L3;
• Y and Z are each independently H or an anionic ligand selected from the group consisting of halogen, OCOR, OCOCF3, OSO2R, OSO2CF3, CN, OH, OR, N(R)2, RS and SH;
• wherein R is as defined above;
• X represents zero, one, two or three substituents selected from the group consisting of alkyl, aryl, halogen, nitro, amide, ester, cyano, alkoxy, cycloalkyl, alkylaryl, heterocyclyl, heteroaryl, an inorganic support and a polymeric moiety;
• anion represents a group bearing a single negative charge;
• and
• (ii) A complex of Formula A1″, A2″ and A3″:
• wherein
• L1 is selected from the group consisting of phosphine (PRaRb), phosphite P(ORa)(ORb), phosphinite P(ORa)(Rb), amine (NRaRb), imine, oxazoline, sulfide (SRa), sulfoxide (S(═O)Ra), heteroaryl containing at least one heteroatom selected from nitrogen and sulfur;
• arsine (AsRaRb), stibine (SbRaRb) and a N-heterocyclic carbene represented by the structures:
• L2 is a mono-dentate two-electron donor selected from the group consisting of CO, PRaRbRc, P(ORa)(ORb)(ORc), NO+, AsRaRbRc, SbRaRbRc, SRaRb, nitrile (RCN), isonitrile (RNC), N2, PF3, CS, heteroaryl, tetrahydrothiophene, alkene and alkyne;
• L3 is absent or is L2;
• Y and Z are each independently H or an anionic ligand selected from the group consisting of H, halogen, OCOR, OCOCF3, OSO2R, OSO2CF3, CN, OR, N(R)2 and RS;
• Ra, Rb and Rc are each independently alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkylcycloalkyl, alkylaryl, alkylheterocyclyl or alkylheteroaryl;
• R, R1, R2 and R3 are each independently H, alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkylcycloalkyl, alkylaryl, alkylheterocyclyl or alkylheteroaryl;
• X1 represents zero, one, two or three substituents and X2 represents zero, one, two, three or four substituents, wherein each such substituent is independently selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkylcycloalkyl, alkylaryl, alkylheterocyclyl, alkylheteroaryl, halogen, nitro, amide, ester, cyano, alkoxy, alkylamino, arylamino, an inorganic support and a polymeric moiety;
• and
• anion represents a group bearing a single negative charge.