In situ generation and reactions of (phenylcarbene)pentacarbonyltungsten(0) with alkenes - role of puckered metallocyclobutanes in determining the stereochemistry of cyclopropane formation

Abstract

CDCl3) 6 7.57 (m, 15 H, ph3P+-), 6.97 (m, 5 H. CsH5). 3.62 (d Of t, 1 H, h p -~

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…Naturally, such interference does not apply to benzylidene transfer reactions which can efficiently and stereoselectively be effected with (CO) 5 WdCH-C 6 H 4 R [17][18][19] or Cp(CO)(L)MdCH(C 6 H 4 R) + (M ) Fe, Ru; L ) CO, PPh 3 ; R ) p-H, p-F, p-Me, p-OMe). [20][21][22] Benzylidene transfer from (CO) 5 WdCHPh to the thiocarbonyl group in thiobenzophenones results in thiirane complexes.…”

Dihydropyridines in Organometallic Synthesis. Formation of Pyridine and Dihydropyridine-Stabilized Alkylidene Complexes of Tungsten(0) and Chromium(0) from Fischer Carbene Complexes: Structure and Reactivity

“…A slightly modified method gave, later on, access to a series of diarylcarbene complexes of chromium and tungsten . Attempts to synthesize and isolate other simple metal(0) alkylidene complexes of this type either failed due to fast β-elimination reactions or led to unexpected dinuclear complexes (Scheme ). − However, a benzylidene complex, 3 , of W(0) (and later of Cr(0)) could be prepared in a two-step process by reacting successively (CO) 5 WC(OEt)Ph ( 1 ) with a complex hydride, KHB(OiPr) 3 , and an acid. − Due to its unstability, complex 3 could only be handled at low temperature (−80 to −20 °C). Its reaction with phosphines led however to stable phosphorus ylides 4a , b .…”

Preparation and reactions of alkyl- and arylpentacarbonyltungsten anions

“…WCHCeHs 3. The preparation of carbene complexes by hydride abstraction with (CeHsHC4 has been reported 32.…”