Enantioselective Synthesis of Multifunctionalized 4<i>H</i>-Pyrans via Formal [4 + 2] Annulation Process by Bifunctional Phosphonium Salt Catalysis
作者:Jia-Hong Wu、Jianke Pan、Juan Du、Xiaoxia Wang、Xuemei Wang、Chunhui Jiang、Tianli Wang
DOI:10.1021/acs.orglett.9b04079
日期:2020.1.17
highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional phosphonium salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to
在双功能phospho盐催化下,已开发出了一种高对映选择性的正式[4 + 2]环,其中涉及缺电子的丙二烯作为C2-合成子。通过这种催化方案,可以容易地以高收率(高达99%)和出色的非对映和对映选择性(高达> 20:1 dr,高达> 99.9)制备各种合成有趣且高度官能化的手性4H-吡喃衍生物。 %ee)。该方法的实用性和实用性通过克级反应和简便的制备方法得到了证明。值得注意的是,这是在相转移催化系统下涉及烯丙基反应物的不对称环化反应的第一个例子。