Asymmetric Diels-Alder
Reactions of Sulfonyl-Functionalized α,β-Unsaturated
Ketones with Cyclopentadiene Catalyzed by Chiral Lewis Acid
作者:Wen Pei、Yu-Guang Wang、Yong-Jiang Wang、Li Sun
DOI:10.1055/s-0028-1083167
日期:——
Asymmetric Diels-Alder reactions of (E)-1 -substituted sultonyl-3-penten- z-ones witn cyclopentadiene catalyzed Dy a chiral titanium reagent were investigated. The enantioselectivity was studied with different substituents in the position of sulfonyl moiety. 6-Methyl-5-(substituted-sulfonylacetyl)bicyclo[2.2.1]hept2-enes (4) were prepared in high yield with high optical purity. The absolute configuration
研究了 (E)-1-取代的磺酰基-3-戊烯-酮与环戊二烯催化的手性钛试剂 Dy 的不对称 Diels-Alder 反应。用磺酰基部分位置上的不同取代基研究了对映选择性。以高收率和高光学纯度制备了 6-甲基-5-(取代的磺酰基乙酰基)双环[2.2.1]庚二烯 (4)。环加合物的绝对构型由化合物 4 的替代合成路线确定,化合物 4 通过酰基恶唑烷酮 6 与环戊二烯的不对称 Diels-Alder 反应制备,然后将取代的磺酰基甲基锂亲核加成到产物中。制备并研究了具有 >99% ee 的 (5R,6S)-6-methyl-5-(phenylsulfonylacetyl)bicyclo-[2.2.1]hept-2-ene (4a) 晶体。