Method for asymmetric synthesis

A process for preparing chiral compounds by reacting a prochiral compound comprising at least one ethylenically unsaturated double bond with a substrate in the presence of a chiral catalyst comprising at least one transition metal complex with ligands which each have a pnicogen-comprising or pseudopnicogen-comprising group and at least one functional group capable of forming intermolecular, noncovalent bonds, with the complex comprising ligands dimerized via intermolecular noncovalent bonds,

• wherein the ligands comprise at least one structural element of the formula I.a or I.b
• or tautomers thereof, where
• Pn is selected from a pnicogen atom or a coordinating atom of a pseudopnicogen-comprising group,
• R1, R2 are each, independently of one another, alkyl, alkoxy, cycloalkyl, cycloalkoxy, heterocycloalkyl, heterocycloalkoxy, aryl, aryloxy, hetaryl or hetaryloxy or
• R1 and R2 together with the phosphorus atom to which they are bound form a 4- to 8-membered heterocycle which may additionally be fused with one, two or three cycloalkyl, heterocycloalkyl, aryl or hetaryl groups, where the heterocycle and, if present, the fused-on groups may each bear, independently of one another, one, two, three or four substituents selected from among alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, COORc, COO−M+, SO3Rc, SO3−M+, PO3(Rc)(Rd), (PO3)2−(M+)2, NE4E5, (NE4E5E6)+X−, ORe, SRe, (CHRf(CH2O)yRe, (CH2CH2NE4)yRe, halogen, nitro, acyl and cyano,
• where
• Rc and Rd are identical or different radicals selected from among hydrogen, alkyl, cycloalkyl, aryl and hetaryl,
• Re, E4, E5, E6 are identical or different radicals selected from among hydrogen, alkyl, cycloalkyl, aryl and hetaryl,
• Rf is hydrogen, methyl or ethyl,
• M+is a cation equivalent,
• X−is an anion equivalent and
• y is an integer from 1 to 240,
• R3 is hydrogen, alkyl alkoxy, cycloalkyl, cycloalkoxy, heterocycloalkyl, heterocycloalkoxy, aryl, aryloxy, hetaryl or hetaryloxy,
• X is a C1-C5-alkylene bridge which, depending on the number of bridge atoms, may have one or two double bonds and/or one, two, three or four substituents selected from among alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, carboxylate, sulfonate, phosphonate, NE1 E2 (E1, E2=hydrogen, alkyl, cycloalkyl, acyl or aryl), hydroxy, thiol, halogen, nitro, acyl and cyano,
• where the cycloalkyl, aryl and hetaryl substituents may additionally bear one, two or three substituents selected from among alkyl, alkoxy, halogen, trifluoromethyl, nitro, alkoxycarbonyl and cyano, and/or one or two nonadjacent bridge atoms of the C1-C5-alkylene bridge X may be replaced by a heteroatom or a heteroatom-comprising group and/or the alkylene bridge X can have one or two aryl and/or hetaryl groups fused onto it, and
• where the fused-on aryl and hetaryl groups may each bear one, two or three substituents selected from among alkyl, cycloalkyl, aryl, alkoxy, cycloalkoxy, aryloxy, acyl, halogen, trifluoromethyl, nitro, cyano, carboxyl, alkoxycarbonyl and NE1E2 (E1 and E2=hydrogen, alkyl, cycloalkyl, acyl or aryl), and
• Y is O, S or NR4, where R4 is hydrogen, alkyl cycloalkyl, heterocycloalkyl, aryl or hetaryl,
• where two or more of the radicals X and R1 to R4 together with the structural element of the formula I.a or I.b to which they are bound may form a monocyclic or polycyclic compound.