Catalyst to the hydroformylation of olefins, comprising amidinato-​silylene ligands and its use

Amidinato-​supported bis-​silylenes I (1, R1-​R3 = alkyl, aryl, alkenyl, cycloalkyl, heterocycle; L = O, benzenediolate, pyridinediaminate, ferrocenediyl, preferably, L = 1,​1'-​ferrocenediyl)​, useful as ligands for transition metal complexes, active as catalysts in alkene hydroformylation and prodn. of aldehydes, were prepd. by metalation of linker precursors H2L and reaction with amidinato-​supported chlorosilylenes R2CNR1NR3SiCl; subsequent complexation of I with transition metal precursors, preferably, with HRh(CO)​(PPh3)​3 produced active and stable hydroformylation catalysts. In an example, lithiation of 3.23 mmol of ferrocene with BuLi​/TMEDA gave the dilithioferrocene intermediate, which was reacted with 6.45 mmol of (N,​N'-​di-​tert-​butylbenzamidinato)​chlorosilicon in 30 mL of toluene for 12 h at 20°, giving the invented ligand, 1,​1'-​[PhC(NtBu)​2Si]​2(C5H4)​2Fe (1a)​. Complexation of 1a with HRh(CO)​(PPh3)​3, taken in equimol. amts. in C6D6 gave the rhodium complex [[1,​1'-​[PhC(NtBu)​2Si]​2(C5H4)​2Fe]​RhH(CO)​(PPh3)​] (2a)​. Hydroformylation of styrene at 100° and CO​/H2 pressure of 30 atm, catalyzed by HRh(CO)​(PPh3)​3/1a (1:3)​, exhibited TOF of 9075 h-​1, compared to 3007 in the same conditions catalyzed by HRh(CO)​(PPh3)​3/Xantphos (1:3) combination.