Ligands for asymmetric reactions

A compound of the formula I,

• wherein Y1 and Y2 are, independently of each other, P(═O), P(═S) or P;
• Z1, Z2, Z3 and Z4 are, independently of each other, halogen or an unsubstituted or substituted moiety selected from the group consisting of aryl, heterocyclyl, cycloalkyl, aryl-lower alkyl, heterocyclyl-lower alkyl, cycloalkyl-lower alkyl, alkyl, aryloxy, heterocyclyloxy, cycloalkoxy, aryl-lower alkoxy, heterocyclyl-lower alkoxy, cycloalkyl-lower alkoxy and alkoxy;
• or —N(Q)2 wherein Q is unsubstituted or substituted alkyl or wherein N(Q)2 forms an unsubstituted or substituted heterocycle optionally containing further heteroatoms;
• or hydrogen;
• or one or all of the pairs (i) Z1 and Z2, and (ii) Z3 and Z4, form bridges of any one of the formulae (A), (B), (C), (D), (E) and (F)
• wherein
• m is 1 to 5;
• n is 1 to 6;
• q is 0 to 6;
• A is a substituent, where the substituent or substituents A are independently unsubstituted or substituted moieties selected from the group consisting of alkyl, aryl, lower alkoxy or di-(lower alkyl)-amino, and/or two moieties A together form a methylendioxy or a C3-C7-alkylene bridge that are unsubstituted or substituted;
• or pairs of substituents A together with the binding carbon atoms form an unsubstituted or substituted annelated ring;
• or in formula (B), if m is 2 to 5, pairs of substituents A together with the binding carbon atoms form an unsubstituted or substituted annelated ring;
• or in formula (C), pairs of substituents A together with the binding carbon atoms form an unsubstituted or substituted annelated ring;
• X4 is, independently of each other, O or NR5;
• and
• R5 is independently hydrogen or an unsubstituted or substituted moiety selected from the group consisting of alkyl, aryl, cycloalkyl, heterocyclyl, aryl-lower alkyl, cycloalkyl-lower alkyl heterocyclyl-lower alkyl, SO2R, SO3R, SO2NR, C(═O)R, C(═O)OR and C(═O)NR;
• while the residues from Z1, Z2, Z3 and Z4, as far as they are not involved in bridge formation, are as defined above;
• X1 is NR, O or S;
• X2 is CHR1 or CR1;
• X3 is CHR2 or NR2 or, if X2 is CR1, X3 is CR2 or N;
• R, R1 and R2, independently of each other, are hydrogen or an unsubstituted or substituted moiety selected from the group consisting of alkyl, aryl, cycloalkyl, heterocyclyl, aryl-lower alkyl, cycloalkyl-lower alkyl and heterocyclyl-lower alkyl or R1 and R2 together form an annealed unsubstituted or substituted mono-, bi- or polycyclic ring system.