OXYMETHYLATION OF ALKYLIRON COMPLEX CPFE(CO)2-R WITH HYDROSTANNANE AND HYDROSILANE, LEADING TO R-CH2OH DERIVATIVES - RELATED REACTIONS OF CPFE(CO)(L)-R AND CPFE(CO)(L)-C(O)R TYPE ORGANOIRON COMPLEXES AND THE MOLECULAR-STRUCTURE OF TRANS-CPFE(H)(CO)(SNPH3)2

Thermal reaction of an alkyliron complex CpFe(CO)2-R (1) (R = CH2CH2Ph) and acyliron complexes, CpFe(CO)2-C(O)R (3) and CpFe(CO)(PPh3)-C(O)R (4) with 3 equiv of HMMe3 (M = Sn, Si) affords the oxymethylated product R-CH2OX (5) in excellent yields accompanied by the formation of CpFe(H)(L)(MMe3)2 (9a L = CO, M = Sn; 10a L = CO, M = Si; 11 L = PPh3, M = Sn). The reaction of a phosphine-substituted alkyliron complex CpFe(CO)(PPh3)-R (2) under similar reaction conditions gives R-H (7). On the other hand, irradiation of the organoiron complexes 1-4 in the presence of HMMe3 Produces 7 as a major product with the exception of 3 + HSnMe3 where R-CHO (6) is obtained. The thermal reaction is found to consist of two consecutive reactions, i.e., formation of 6 and reduction of 6 to 5. When HSnMe3 is used as a limiting substrate (HSnMe3/1 less-than-or-equal-to 2), R-CHO is actually formed in good yield. The second step is proved to be catalyzed by various iron complexes such as 9a, Fp-Me, Fp-C(O)Me, and Fp2. The relationship among 1-4 and the coordinatively unsaturated species is also discussed. The molecular structure of trans-CpFe(H)(CO)SnPh3)2 (9C) obtained by the thermal reaction of 1 with HSnPh3 has been determined by X-ray diffraction study. The unit cell contains two crystallography independent molecules with the essentially same geometry. The structure is described as a four-legged piano stool structure with the two SnPh3 groups occupying the mutually trans basal positions. The contribution of the eta-2-coordination mode of the H-Sn bond may be negligible on the basis of the molecular structure as well as the small 2J(H-Fe-Sn) values. Crystal data for 9c: space group P1BAR, a = 16.248 (7) angstrom, b = 19.646 (6) angstrom, c = 11.443 (5) angstrom, alpha = 93.32 (3)-degrees, beta = 93.67 (4)-degrees, gamma = 97.09 (3)-degrees, V = 3609 (3) angstrom 3, Z = 4, R = 0.0312, R(w) = 0.0379.