Reductive Cleavage of Carbon Monoxide by a Disilenide

Abstract

The complete reductive cleavage of the triple bond in carbon monoxide was achieved using a lithium disilenide at room temperature. The C-C-coupled product can be regarded as a silanone dimer with pending alkyne and silirene moieties and incorporates two equivalents of CO per disilenide unit. A formation mechanism via ketenyl intermediates is proposed on the basis of DFT calculations and elucidated experimentally by employing Group 6 metal carbonyls as both stabilizing entity and source of CO in the reaction with disilenide. The isolation of cyclic silylene complexes with weakly donating ketenyl donor groups further supports the mechanistic scenario.

The Reactions of Carbon Monoxide with Silyl and Silenyl Lithium – Synthesis and Isolation of the First Stable Tetra‐Silyl Di‐Ketyl Biradical and 1‐Silaallenolate Lithium

“…In contrast to the rich organolithium chemistry with CO, the chemistry of silyl lithium compounds with CO is almost unknown, with only one reported example from 1970 . The reaction of disilenyl lithium with CO has been described recently …”

Elektrophile Formylierung von Aromaten durch silyliumionvermittelte Aktivierung von Kohlenmonoxid

“…[3][4][5] Der genaue Mechanismus ist noch immer Gegenstand von Diskussionen, beinhaltet aber wahrscheinlich die Beteiligung von protoniertem CO als Formylierungsmittel. [11] Die dazugehçrigen Lewis-Addukte weisen einen energetisch stabileren C-gebundenen Carbonylliganden auf,w eil das s-symmetrische hçchst besetzte Molekülorbital (HOMO) des CO mehr am Kohlenstoffatom lokalisiert ist. [6,7] Ersteres war mit 38 kcal mol À1 als stabiler in der Gasphase berechnet wor-den [6a] und wurde in der kondensierten Phase spektroskopisch nachgewiesen.…”

The Transition‐Metal‐Like Behavior of B2(NHC)2 in the Activation of CO: HOMO–LUMO Swap Without Photoinduction

“…[5] Bertrand and his co-workers fixed CO to stable acyclica nd cyclic alkyl amino carbenes, [6] and Braunschweig et al synthesized ab orylene dicarbonyl complex. [11] Themost exciting experimental report is by Braunschweig et al who found that diboryne (B B) stabilized by a Nheterocyclic carbenes (B 2 (NHC R ) 2 ) [12] can bind and generate the asymmetrically bridging CO ligands,w hich can be drastically activated to eventually form CÀCb onds. [9] Interestingly,D obrovetsky and Stephan developed am etalfree mixture of B(C 6 F 5 ) 3 and tBu 3 Pw hich can effectively reduce CO in syngas.…”