Synthesis of silyl, germyl, and phosphino‐substituted acylketenes from pivaloylethoxyacetylene

Abstract

The reaction of pivaloylethoxyacetylene with silicon halides, which has been found to occur as a 1,4-addition, leads to allenic ethers, which readily eliminate ethyl halides and are converted to previously unknown types of ketenes-stable element-substituted acylketenes. Gerrnanium-substituted acylketenes are also formed; however, clear evidence of 1 ,Caddition of germanium halides was not obtained. In the reaction between PhzPCl and pivaloylethoxyacetylene, phosphorus (111) substituted acylketenes initially formed underwent rapid [3 + 31 cyclodimerization.

Stable Ketenyl Anions via Ligand Exchange at an Anionic Carbon as Powerful Synthons**

“…Furthermore, the structures of 4 and 5 in the solid state were determined by single crystal X‐ray crystallography (Figures 6a and 6b). This analysis represents the first example of a crystallographically characterized germanyl‐substituted ketene structure [39] . Even more remarkable is that copper ketenyl anion complexes were hitherto unknown species.…”

“…This analysis represents the first example of a crystallographically characterized germanyl-substituted ketene structure. [39] Even more remarkable is that copper ketenyl anion complexes were hitherto unknown species. The facile access to 4 and 5 showcases the exciting ability of the ketenyl anion for constructing ketenes with previously uncharted substituents.…”