An expedient synthesis of highly functionalized 1,3-dienes by employing cyclopropenes as <i>C</i><sub>4</sub> units
Chengzhou Jiang, Jiamin Wu, Jia‐Bin Han, Kai Chen, Qian Yang, Zhengyu Zhang, Yaojia Jiang
Abstract
An efficient method has been described to synthesize dicarbonyl functionalized 1,3-dienes by cleaving the C[double bond, length as m-dash]C bond of enaminones with cyclopropenes in the presence of a rhodium catalyst. The acetate-substituted cyclopropenes are judiciously chosen as standard C4 units of 1,3-diene precursors. The reactions are believed to undergo a unique cutting and insertion process, involving a C[double bond, length as m-dash]C bond cleavage of the enaminone and insertion of a new C(sp2) source with the formation of two C-C single bonds. A broad range of substrates can be used to synthesize the corresponding 1,3-dienes under very mild reaction conditions, including low catalyst-loading, ambient temperature, and a neutral reaction solvent.