Asymmetric Synthesis of cis-3,4-Disubstituted Chromans and Dihydrocoumarins via an Organocatalytic Michael Addition/ Hemiacetalization Reaction
作者:Dieter Enders、Chuan Wang、Xuena Yang、Gerhard Raabe
DOI:10.1002/adsc.201000659
日期:2010.11.22
of diphenyl prolinol trimethylsilyl ether, cis-3,4-disubstituted chromanols are obtained in high to excellent yields (81–98%) and stereoselectivities (dr: 86:14 to >99:1, ee 96 to >99%). The corresponding disubstituted chromans are available by dehydroxylation of the domino products in good to excellent yields (58–95%). Furthermore, oxidation of the domino products with pyridinium chlorochromate provided
已经开发了各种醛和邻硝基乙烯基苯酚之间的有机催化多米诺迈克尔/半缩醛化反应。在二苯基脯氨醇三甲基甲硅烷基醚的催化下,可获得高至优异的收率(81–98%)和立体选择性(dr:86:14至> 99:1,ee 96至> 99%)顺式-3,4-二取代的色醇)。通过对多米诺骨牌产品进行脱羟基处理,可以得到相应的二取代的苯并二氢吡喃,收率好至极好(58–95%)。此外,用氯铬酸吡啶鎓氧化多米诺产物可提供高产率(65-83%)的3,4-二氢香豆素,而没有任何差向异构。