Preferred kinetic migration of methyl and preferred thermodynamic migration of phenyl in conversion of cis-acetylbenzoyltetracarbonylrhenate(I) to cis-benzoylmethyltetracarbonylrhenate(I) and cis-acetylphenyltetracarbonylrhenate(I)

Abstract

Reaction of CH3Li with (COLReCOQHs or reaction of CeHsLi with (CO)sReCOCH3 produce N(CH3)4+[m-(CO)4Re(COCH3)(COC6H5)]-(2). Thermolysis of 2 at 69 °C produces a 98:2 mixture of N(CH3)4+[m-(CO)4Re(C6H5)-(COCH3)]-(4) and N(CH3)4+[m-(CO)4Re(CH3)(COC6H5)]-( 5), which equilibrate under these conditions. Reaction of 2,4, or 5 with P(CH2CH3)3 gives N(CH3)4+[/ac-(CO)3[P(CH2CH3)3Re(COCH3)(COC6H5)]" (7a). The rate of phosphine addition to 5 to give 7a is 28 times faster than the isomerization of 5 to 4. This implies that methyl migration to rhenium occurs 28-29 times faster than phenyl migration to rhenium in the five-coordinate bisacyl intermediate [(CO)3Re(COCH3)-(COC6H5)]-( 6).

Manganese-Mediated C–C Bond Formation: Alkoxycarbonylation of Organoboranes

“…Compound 2 was unstable in solution and fully degraded over the course of several days. This decomposition has been observed before for similar Mn/Re complexes 35,41 and is presumably induced by both heat and light (although attempted crystallization at −80 °C in the dark did not appreciably stop the decomposition). Gratifyingly, crystals suitable for XRD could be obtained for Mn-isopropoxo-dimer 3.…”

Technetium and Rhenium

“…Thus by reaction with L = P(OMe 3 ]-. 435 It should be noted that for L = CO (at 63 p.s.i. and 67 °C) only 38% conversion to the corresponding diacyl derivative is observed over an 8 h period.…”

“…and 67 °C) only 38% conversion to the corresponding diacyl derivative is observed over an 8 h period. 435 Through analysis of the rates of these reactions as well as those of the isomerization of the monoacyl anions, the ratio of the relative kinetic migrating tendencies of the two groups (Me:Ph) was determined to be 29:1. 435…”

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]

“…If a complex bears both alkoxycarbonyl (or acyl) and terminal carbonyl ligands, the addition of a nucleophile may occur at any of the two ligands (Scheme ). For COZ being acyl (Z = R), pathway (a) is observed in the example of reaction 3. , For COZ being alkoxycarbonyl (Z = OR), the unique following example shows a nucleophilic attack apparently according to pathway (a) (eq 4) 5b. When no terminal carbonyl is present, the nucleophilic attack on the COZ group (pathway (b)) has been observed (eq 5) …”