Study of the Nucleophilic Addition of Alcoholates on cis-Fe(R)(R‘)(CO)3L (R, R‘ = Alkyl, Alkoxycarbonyl, Alkyloxalyl; L = CO, P(OEt)3) and the First Characterization of a Tris(alkoxycarbonyl) Complex: K[Fe(CO2tBu)3(CO)3]

The nucleophilic additions of alcoholates (MeONa or tBuOK) on the complexes cis -Fe(R)(R‘)(CO) 3 L (R, R‘ = CO 2 Me, CO 2 tBu, CH 2 CO 2 Me, COCO 2 Me; L = CO, P(OEt) 3 ) occur at one terminal carbonyl ligand to give the new [Fe(R)(R‘)(CO 2 R‘‘)(CO) 2 L] - anions. No transesterification ( via addition at an alkoxycarbonyl ligand) is observed. An X-ray diffraction study gives the space group P 2 1 / c for K[Fe(CO 2 tBu) 3 (CO) 3 ] (resulting from the addition of KOtBu on Fe(CO 2 tBu) 2 (CO) 4 ), which is better described as the dimer K 2 Fe 2 (CO 2 tBu) 6 (CO) 6 ·H 2 O·THF.