Formation and aromatization of strained bicyclic pyrazolidines via tandem reaction of alkyl 2-aroyl-1-chlorocyclopropanecarboxylates with acylhydrazones
Cycloaddition Reactions of Alkyl Cyclopropenecarboxylates Generated in situ with Nitrones: Construction of Substituted Pyrroles and 1,2-Oxazinanes
作者:Junhao Hu、Min Zhang、Yuefa Gong
DOI:10.1002/ejoc.201403551
日期:2015.3
A highly regioselective [3+2] cycloadditionreaction of nitrones 1 with alkyl 2-aroylcyclopropenecarboxylates generated in situ from alkyl 2-aroyl-1-chlorocyclopropanecarboxylates 2 under basic conditions is described. The reaction proceeded readily to afford ring-fused isoxazolidines 3 in moderate-to-high yields. The strained ring-fused cycloaddition products were selectively transformed into the
A Two-Step Sequence to Ethyl α-Fluorocyclopropanecarboxylates Through MIRC Reaction of Ethyl Dichloroacetate and Highly Regioselective Fluorination
作者:Min Zhang、Yuefa Gong、Weizhou Wang
DOI:10.1002/ejoc.201300978
日期:2013.11
A two-stepsequence to ethylα-fluorocyclopropanecarboxylates has been developed. Ethyl α-chlorocyclopropanecarboxylates were first obtained through a Michael-initiated ring closure reaction of terminal electron-deficient olefins with ethyl 2,2-dichloroacetate under mild basic conditions. Subsequent smooth conversion into the corresponding monofluorinated analogues in good yields was through a halogen
Highly Regioselective Cascade Formal Nucleophilic Substitution and Aldol Condensation of 2-Aroyl-1-chlorocyclopropanecarboxylic Esters
作者:Min Zhang、Junkai Guo、Yuefa Gong
DOI:10.1002/ejoc.201301866
日期:2014.3
cascade formal nucleophilic substitution and aldol reaction of 2-aroyl-1-chlorocyclopropanecarboxylic esters with salicylic aldehydes is described. Under basic conditions, 2-aroyl-1-chlorocyclopropanecarboxylic esters are easily converted into cyclopropene intermediates by simple 1,2-elimination of hydrogen chloride. This highly reactive cyclopropene quickly combines with salicylic aldehyde through a
Direct Construction of the 9<i>H</i>-Pyrrolo[1,2-<i>a</i>]azepin-9-amine Skeleton<i>via</i>[4+3] Annulation of Alkyl 2-Aroyl-1-chlorocyclo- propanecarboxylates
作者:Junhao Hu、Yang Liu、Yuefa Gong
DOI:10.1002/adsc.201500376
日期:2015.9.14
[4+3] annulation between donor–acceptor reagents derived from 1H‐pyrrole‐2‐carbaldehydes and alkyl2‐aroyl‐1‐chlorocyclopropanecarboxylates. This transition metal‐free domino reaction proceeded quickly under mild basic conditions, affording potentially bioactive azepine derivatives in moderate to high yields with high diastereoselectivities (up to >20:1).
一种重要的9 H-吡咯并[1,2- a ] azepin-9-胺的直接非对映选择性合成方法是通过衍生自1 H-吡咯-2-碳醛的供体-受体试剂之间的碱促进[4 + 3]环化而建立的和2-芳酰基-1-氯环丙烷羧酸烷基酯。这种无过渡金属的多米诺骨反应在温和的碱性条件下快速进行,从而以中等至高收率提供了具有高非对映选择性(高达> 20:1)的潜在生物活性a庚因衍生物。