Highly Enantioselective Synthesis of Spiro[cyclohexanone-oxindoles] and Spiro[cyclohexanone-pyrazolones] by Asymmetric Cascade [5+1] Double Michael Reactions
作者:Bin Wu、Jian Chen、Mei-Qiu Li、Jin-Xin Zhang、Xiao-Ping Xu、Shun-Jun Ji、Xing-Wang Wang
DOI:10.1002/ejoc.201101529
日期:2012.3
The asymmetric catalytic synthesis of naturally occurring and biologically active spiro compounds is a challenge for modern chemical methodology. Here we report the construction of spiro compounds through cascade [5+1] double Michael reactions between divinyl ketones and N-unprotectedoxindoles or N-phenyl-protected pyrazolones catalyzed by a combination of the easily available 9-amino-9-deoxy-epi-quinine
天然存在和生物活性螺环化合物的不对称催化合成是现代化学方法的挑战。在这里,我们报告了通过二乙烯基酮和 N-未保护的羟吲哚或 N-苯基保护的吡唑啉酮之间的级联 [5+1] 双迈克尔反应构建螺环化合物,该反应由易于获得的 9-氨基-9-脱氧-表奎宁与 N-Boc-D-苯基甘氨酸。以高产率(高达 98%)和立体选择性(高达 >20:1 dr,99% ee)获得了所需的多立体螺环[环己酮-羟吲哚和 -吡唑啉酮]。