Nitroso Compounds Serve as Precursors to Late-Metal η²(N,O)-Hydroxylamido Complexes

Abstract

The metallacyclobutene complex (η 5 -C 5 H 5 )(PPh 3 )Co-{κ 2 (C 1 ,C 3 )-C(SO 2 Ph)dC(SiMe 3 )CH(CO 2 Et) undergoes a regioand stereoselectiVe reaction with both nitrosobenzene and 2-methyl-2-nitrosopropane to giVe ring-expanded metallacycles with an η 2 (N,O)-hydroxylamido ligand. These transformations represent a new synthetic route toward late-metal η 2 (N,O)hydroxylamido complexes.

α-Diimine synthesis via titanium-mediated multicomponent diimination of alkynes with C-nitrosos

“…The tendency of C-nitrosos to undergo Diels-Alder-type cycloaddition reactions is well known, 62,63 but examples of this process with metallacycles are scarce. 64,65 Titanium b-diketiminate complexes, which differ from diazatitanacyclohexadienes by a degree of unsaturation, have also been observed to undergo [4 + 2]-cycloaddition with ketenes. 66,67 IM4 then undergoes rate-determining (12.6 kcal mol À1 ) retro-[4 + 2] cycloaddition to extrude nitrile, forming azaoxatitanacycle IM5.…”

α-Diimine Synthesis via Titanium-Mediated Multicomponent Diimination of Alkynes with C-Nitrosos

“…This process can be further visualized using IBO analysis (Figure 8a Diels-Alder-type cycloaddition reactions is well known, [60][61] but examples of this process with metallacycles are scarce. [62][63] Titanium β-diketiminate complexes, which differ from diazatitanacyclohexadienes by a degree of unsaturation, have also been observed to undergo [4+2]-cycloaddition with ketenes. [64][65] IM4 then undergoes rate-determining (12.6 kcal/mol) retro-[4+2] cycloaddition to extrude nitrile, forming azaoxatitanacycle IM5.…”

Cobalt, rhodium and iridium

“…The metallacyclobutene complex 6 was found to undergo a regio and stereo-selective reaction with PhNO to afford ring expanded metallacycles 7a and 7b (8 : 1 cis : trans, 71% combined yield). 10 Attempts to separate the two isomers by chromatography and recrystallisation were unsuccessful. Triangular Co(III), Rh(III) and Ir(III) dithiolene complexes 8a-c have been synthesised (up to 90% yield) from C 6 (SH) 6 and either Co(Cp*)(CO)I 2 or [M(m-Cl)(Cl)(Cp*)] 2 (M = Rh, Ir) under basic conditions.…”