Reductive Cleavage of Carbon Monoxide by a Disilenide

Abstract

The complete reductive cleavage of the triple bond in carbon monoxide was achieved using al ithium disilenide at room temperature.The CÀC-coupled product can be regarded as as ilanone 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 6m etal 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.

Silicon‐Mediated Coupling of Carbon Monoxide, Ammonia, and Primary Amines to Form Acetamides

“…Among the most important reactions in (bio)organic chemistry is the sequential COÀNH (amide) bond formation because of its widespread occurrence in nature and role for pharmaceuticals,a grochemicals,a nd dyes. [9] Herein, we report on the unexpected formation and striking mechanism of the acetamides 6a,b through ammonolysis of the disilaketene 2a. [4] Thee nergetically more demanding reductive cleavage of N 2 as as ource of nitrogen and the homologation of CO,t wo simple diatomic molecules with the strongest known bonds in chemistry,could be achieved in ah afnocene-mediated coupling reaction to yield oxamide, H 2 N À CO À CO À NH 2 .…”

“…, C1ÀC2 1.450(9), Si2ÀN5 1.809(3), C1ÀN5 1.414 (9). Bond angles [8 8]: Si1-C2-C1 123.01(3), C2-C1-O31 19.67(1), C2-C1-N5 122.30 (5).…”

“…[6] With the disilaketene 2a in hand, we now learned that its ketene moiety possesses an unprecedented reactivity towards ammonia and primary amines,a ffording acetamides.T his type of reactivity is currently unknown for diorganoketenes [7,8] and disilaketenes. [9] Herein, we report on the unexpected formation and striking mechanism of the acetamides 6a,b through ammonolysis of the disilaketene 2a. Tr eatment of 2a with NH 3 under ambient conditions (1 bar,2 98 K) provided acetamide 6a along with the corresponding Fc-disiloxanediamine 5a,w hich could be crystallized from THF at À30 8 8C.…”

Silicon‐Mediated Coupling of Carbon Monoxide, Ammonia, and Primary Amines to Form Acetamides

“…3b crystallizes in the triclinic space group P " 1w ith an on-planar six-membered Si 2 C 2 NO dlactam core as the central structural motif (Figure 2). The 9, Si2ÀN5 1.809(3), C1ÀN5 1.414 (9). Bond angles [8 8]: Si1-C2-C1 123.01(3), C2-C1-O31 19.67 (1), C2-C1-N5 122.30 (5).…”

“…[6] With the disilaketene 2a in hand, we now learned that its ketene moiety possesses an unprecedented reactivity towards ammonia and primary amines,a ffording acetamides.T his type of reactivity is currently unknown for diorganoketenes [7,8] and disilaketenes. [9] Herein, we report on the unexpected formation and striking mechanism of the acetamides 6a,b through ammonolysis of the disilaketene 2a.…”