4-二甲基氨基或4-甲氧基吡啶与炔二羧酸酯和亚芳基氰乙酸酯的三组分反应显示出非常有趣的分子多样性。多取代的1,8,9,9a-四氢-4 H -1,4-乙基喹啉衍生物,2 H-吡喃-2,3-二羧酸盐和buta-1,3-二烯-1,2,4-三羧酸盐衍生物可以取决于底物和反应条件,可以高收率和良好的非对映选择性形成二价铁。
Palladium-Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with Michael Acceptors: Construction of Vicinal Quaternary Stereocenters
作者:Ajmal Khan、Lei Yang、Jing Xu、Long Yi Jin、Yong Jian Zhang
DOI:10.1002/anie.201407013
日期:2014.10.13
An efficient method for the diastereo‐ and enantioselective construction of vicinal all‐carbon quaternarystereocenters through palladium‐catalyzed decarboxylativecycloaddition of vinylethylenecarbonates with activated Michaelacceptors was developed. By using a palladium complex generated in situ from [Pd2(dab)3]⋅CHCl3 and a phosphoramidite ligand as a catalyst under mild reaction conditions, the
acridones and their cyclo[b ]‐fused derivatives are efficiently constructed by a double annulation of o ‐enoyl arylisocyanides with α , β ‐unsaturated carbonyls under simple metal‐free condition. This protocol is general, efficient and practical, featuring the successive formation of two rings by a one‐pot domino transformation. A tandem process involing an isocyanide‐based [1+4] cycloaddition, an aminofuran‐based
在简单的无金属条件下,通过邻烯基芳基异氰酸酯与α,β-不饱和羰基的双环化,可以有效地构建各种各样的a烯及其环[ b ]稠合衍生物。该协议是通用,高效和实用的,其特点是通过一锅多米诺骨牌变换连续形成两个环。提出了将异氰酸酯基[1 + 4]环加成,氨基呋喃基分子内[4 + 2]环加成,开环和芳构化等串联过程。
Formal Asymmetric Cycloaddition of Activated α,β-Unsaturated Ketones with α-Diazomethylphosphonate Mediated by a Chiral Silver SPINOL Phosphate Catalyst
nonspiro-phosphonylpyrazolines via an asymmetric formal 1,3-dipolar cycloaddition reaction of α-diazomethylphosphonate with activated, acyclic α,β-unsaturatedketones, bearing an additional nitrile electron-withdrawing group, has been developed, utilizing an in situ generated chiral silver phosphate catalyst, affording excellent stereoselectivities (up to 98% ee, 99:1 dr) and yields (up to 95%). A stepwise
Enantioselective [4 + 2]-Annulation of Oxadienes and Allenones Catalyzed by an Amino Acid Derived Phosphine: Synthesis of Functionalized Dihydropyrans
作者:Huanzhen Ni、Weijun Yao、Abdul Waheed、Nisar Ullah、Yixin Lu
DOI:10.1021/acs.orglett.6b00760
日期:2016.5.6
An enantioselective [4 + 2]-annulation process between cyano-activated oxadienes and allenones is developed. An l-valine-derived phosphine was efficient in catalyzing the reaction, and a wide range of highly functionalized dihydropyrans were prepared in high yields and with excellent enantioselectivities.