CuCl-catalyzed cyclization–dimerization reactions of 3-cyclopropylideneprop-2-en-1-ones provide an interesting route to benzofuran-7(3aH)-one derivatives with one highly strained three-membered ring and one four-membered ring via intramolecular cycloisomerization, sequential bimolecular [4 + 2] cycloaddition, opening of the oxa-bridge, and ring contraction. Furthermore, the reaction was monitored by NMR experiments
The tunable nucleophilic nitration of 3-cyclopropylidene-prop-2-en-1-ones with cheap sodium nitrite is described. This transformation proceeds with the assistance of a strained cyclopropane ring and allows for a divergent route to various synthetically useful beta,gamma-dinitro or gamma-mononitro adducts in high yields with exclusive regio- and stereo selectivity. Additionally, a wide array of valuable functionalized N-unprotected pyrroles is achieved from the resulting beta,gamma-dinitro compounds via reductive cyclization strategy.
Hydroxyphosphinylation Reaction of 3-Cyclopropylideneprop-2-en-1-ones via C–P σ-Bond Cleavage
作者:Maozhong Miao、Jian Cao、Xian Huang、Luling Wu
DOI:10.1021/jo400610q
日期:2013.6.21
An unexpected hydroxyphosphinylation of 3-cyclopropylideneprop-2-en-1-ones with phosphines has been observed. This method provides a unique regio- and stereoselective synthesis of highly functionalized 1-dialkylphinyl-3-oxo-(1Z)-alkenyl cyclo-propanols with important potentials. The reaction displays an unusual mechanistic feature-a highly selective cleavage of C-P sigma bonds in phosphines.