Hydroformylation catalyst comprising a complex with ligands having a structure derived from bisphenol A

A process for the hydroformylation of compounds containing at least one ethylenically unsaturated double bond by reaction with carbon monoxide and hydrogen in the presence of a hydroformylation catalyst comprising at least one complex of a metal of transition group VIII with at least one ligand selected from among compounds of the formula I

• where
• A1 is O, S, NRc, SiRdRe or CRfRg, where
• Rc, Rd, Re, Rf and Rg are each, independently of one another, hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, where Rf and Rg together with the carbon atom to which they are bound may also form a 3- to 8-membered carbocycle or heterocycle which may additionally be fused with one, two or three cycloalkyl, heterocycloalkyl, aryl and/or hetaryl groups,
• Y1 and Y2 are, independently of one another, radicals containing at least one phosphorus atom,
• Ra and Rb are, independently of one another, hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl or (CHRiCH2O)xRh, where Rh is hydrogen, alkyl, cycloalkyl or aryl, Ri is hydrogen, methyl or ethyl and x is an integer from 1 to 120, and
• R1, R2, R3, R4, R5 and R6 are each, independently of one another, hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, COORh, COO−M+, SO3Rh, (SO3)−M+, NE1E2, NE1E2E3+X−, alkylene-NE1E2E3+X−, ORh, SRh, (CHRiCH2O)xRh, (CH2N(E1))xRh, (CH2CH2N(E1))xRh, halogen, trifluoromethyl, nitro, acyl or cyano,
• where
• Rh, E1, E2 and E3 are identical or different radicals selected from among hydrogen, alkyl, cycloalkyl and aryl,
• Ri is hydrogen, methyl or ethyl,
• M+ is a cation,
• X− is an anion and
• x is an integer from 1 to 120, or
• R1 and R2 and/or R3 and R4 together with the adjacent carbon atoms of the benzene ring to which they are bound form a fused ring system comprising 1, 2 or 3 further rings.