Radical Synthesis of a Heterobinuclear μ-Oxo Complex: Reaction of V(O)(O-i-Pr)_3 with Ti(NRAr)_3 (R = C(CD_3)_2CH_3, Ar = 3,5-C_6H_3Me_2)

摘要

Titanium reagents that mediate the reduction of carbonyl compounds enjoy widespread utility in a variety of guises. Pinacol couplings and the McMurry reaction are two noteworthy examples. The formation of stable titanium ketyl complexes has recently been demonstrated by addition of ketones to monomeric Ti(OSi-t-Bu_3)_3. Such reactions involve electron transfer to the carbonyl carbon with formation of an M—O linkage and erasure of the carbonyl π nexus. We wondered whether a high-valent metal oxo complex might function similarly upon treatment with a suitable Ti(III) reagent, to furnish a stable heterobinuclear μ-oxo complex. To investigate this possibility, we prepared and characterized Ti(NRAr)_3 (R = C(CD_3)_2CH_3, Ar = 3,5-C_6H_3Me_2) and examined its reaction with V(O)(O-i-Pr)_3 as detailed herein.