Enediolates from carboxylic acids react readily with cyclic α-chloroketones to give the corresponding γ-chloro-β-alkoxycarboxylate intermediates depending on the ring size. Small ring ketones lead to γ-chloro-β-hydroxy acids in a highly stereoselective way, whereas medium ring ketones give a mixture of β,γ-epoxy acids and γ-lactones.
Diastereoselective Cyclopropanation of Ketone Enols with Fischer Carbene Complexes
作者:José Barluenga、Marcos G. Suero、Iván Pérez-Sánchez、Josefa Flórez
DOI:10.1021/ja074363b
日期:2008.3.1
Treatment of aryl/heteroaryl methoxycarbene complexes of chromium with -substituted ketone lithiumenolates between -78 degrees C and room temperature resulted in the diastereoselective synthesis of 1,2,2,3-tetrasubstituted cyclopropanols. An exception has been observed in the reaction with cyclohexanone lithiumenolate that yielded a bicyclic 2-buten-4-olide. 1,2-Dimethoxycyclopropanes and 1-meth
The Mukaiyama reaction of ketene bis(trimethylsilyl) acetals with α-halo acetals
作者:F.W.J. Demnitz
DOI:10.1016/s0040-4039(01)93317-9
日期:——
Ketene bis(trimethylsilyl) acetals were reacted with α-halo acetals giving β-alkoxy-γ-halo acids which were converted to butenolides by reaction with two equivalents of base. This constitutes a novel and short butenolide synthesis.