Phosphine ligands for catalytic reactions

A phosphine ligand having a structure corresponding to formula (I-1),

• or a salt thereof,
• wherein
• V1 and V4 are CR1, wherein R1 is independently, at each occurrence, hydrogen, alkyl or alkoxy;
• V2 and V3 are CR1, wherein R1 is independently, at each occurrence, hydrogen, alkyl or alkoxy;
• V5 and V9 are CR2, wherein R2 is independently, at each occurrence, selected from the group consisting of hydrogen, alkyl, alkoxy and dialkylamino;
• V6 and V8 are CR2, wherein R2 is independently, at each occurrence, hydrogen, alkyl or alkoxy;
• V7 is CR2, wherein R2 is hydrogen or alkyl;
• and
• X is selected from the group consisting of phosphines of formulae 1-1, 1-2, 1-3, 1-4, 1-5, and 1-64;
• wherein R20 is selected from the group consisting of hydrogen, alkyl, aryl, heteroaryl, arylalkyl and heteroarylalkyl, wherein the aryl, heteroaryl, aryl of arylalkyl and heteroaryl of heteroarylalkyl are optionally substituted with at least one of alkyl, alkenyl, alkynyl, alkoxy, cyano, halo, haloalkyl or haloalkoxy.