Palladium-Catalyzed [4 + 2] Cycloaddition of <i>o</i>-(Silylmethyl)benzyl Esters with Ketones: An Equivalent to Oxo-Diels−Alder Reaction of <i>o</i>-Xylylenes
作者:Satoshi Ueno、Masakazu Ohtsubo、Ryoichi Kuwano
DOI:10.1021/ol101792a
日期:2010.10.1
o-(Silylmethyl)benzyl carbonates reacted with various electron-deficient ketones in the presence of a palladium catalyst, affording the [4 + 2] cycloaddition products, isochromanes, in high yields. The palladium-catalyzed cycloaddition is equivalent to the oxo-Diels−Alder reaction of o-xylylene with ketones. The regioselectivities were extraordinarily affected by the structures of the o-xylylene precursors
在钯催化剂的存在下,邻-(甲硅烷基甲基)苄基碳酸酯与各种缺电子的酮反应,以高收率提供了[4 + 2]环加成产物异色烷。钯催化的环加成反应相当于邻二甲苯基与酮的oxo-Diels-Alder反应。区域选择性特别受邻二甲苯前体和酮的结构影响。异常的区域化学反应可能在催化反应中支持两个竞争性反应途径。