890002-97-8Relevant academic research and scientific papers
An expedient synthesis of highly functionalized 1,3-dienes by employing cyclopropenes asC4units
Jiang, Chengzhou,Wu, Jiamin,Han, Jiabin,Chen, Kai,Qian, Yang,Zhang, Zhengyu,Jiang, Yaojia
supporting information, p. 5710 - 5713 (2021/06/16)
An efficient method has been described to synthesize dicarbonyl functionalized 1,3-dienes by cleaving the CC bond of enaminones with cyclopropenes in the presence of a rhodium catalyst. The acetate-substituted cyclopropenes are judiciously chosen as standardC4units of 1,3-diene precursors. The reactions are believed to undergo a unique cutting and insertion process, involving a CC bond cleavage of the enaminone and insertion of a newC(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.
Enantioselective, facially selective carbomagnesation of cyclopropenes
Liu, Xiaozhong,Fox, Joseph M.
, p. 5600 - 5601 (2007/10/03)
Described is the facially selective and enantioselective addition of carbon nucleophiles to prochiral 3-hydroxymethylcyclopropenes. The process creates up to four stereocenters in a tandem addition/capture sequence that combines three simple materials to give complex and diverse products. The asymmetry is induced by the inexpensive and recoverable ligand (S)-N-methylprolinol. The enantioselectivity (90-98% ee with MeMgCl) is high for a range of cyclopropenes and electrophiles. Importantly, the diastereoselectivity is complementary to that obtained by enantioselective cyclopropanation with aryldiazoacetates. High enantioselectivities are obtained only when methoxide is included in the reaction. Evidence is provided that at least two chiral ligands are involved in the enantioselectivity-determining step. Copyright
