Michael Addition–Lactonization of Arylacetyl Phosphonate to β,γ-Unsaturated α-Keto Esters for the Synthesis of Chiral <i>syn</i>-3,4-Dihydropyranones and 5,6-Dihydropyranones
作者:Ming-Liang Zhang、Zhi-Jun Wu、Jian-Qiang Zhao、Yuan Luo、Xiao-Ying Xu、Xiao-Mei Zhang、Wei-Cheng Yuan
DOI:10.1021/acs.orglett.6b02558
日期:2016.10.7
Catalytic asymmetric Michael addition–lactonization of arylacetyl phosphonates to β,γ-unsaturated α-keto esters by a chiral bifunctional thiourea–tertiary amine was established. Using the developed protocol, a range of optically pure syn-3,4-dihydropyranones were generated in good yields with good to excellent stereoselectivities (up to >20:1 dr and 99% ee). Meanwhile, when stoichiometric diisopropylethylamine
建立了手性双官能硫脲-叔胺催化不对称迈克尔加成反应,将芳基乙酰基膦酸酯内酯化为β,γ-不饱和α-酮酯。使用开发的方案,可以以良好的收率和良好的立体选择性(高达> 20:1 dr和99%ee)产生一系列光学纯的syn -3,4-二氢吡喃酮。同时,如果将化学计量的二异丙基乙胺和1,8-二氮杂双环[5.4.0]十一碳-7-烯用作同一反应的碱,则可以中等至良好的产率获得一系列5,6-二氢吡喃酮(53– 75%的产率)。