An expedient synthesis of highly functionalized 1,3-dienes by employing cyclopropenes as C4 units.

An efficient method has been described to synthesis of dicarbonyl functionalized 1,3-dienes by cleaving C=C bond of enaminones with cyclopropenes in completely stereoselectivity. The acetate substituted cyclopropenes are judicious choiced as formal C4 units of 1,3-diene precursors. The reactions are believed to undergo a unique cutting and insertion progress which involving a C=C bond cleavage of enaminone and insertion a new C(sp2) source with two C–C single bonds formations. A broad range of substrates scope can be tolerated to affording the corresponding 1,3-dienes under very mild reaction conditions including low catalyst-loading, ambient temperature and neutral reaction solution.