Tunable Cascade Reactions of Alkynols with Alkynes under Combined Sc(OTf)<sub>3</sub>
and Rhodium Catalysis
作者:Deng Yuan Li、Hao Jie Chen、Pei Nian Liu
DOI:10.1002/anie.201508914
日期:2016.1.4
Two tunablecascadereactions of alkynols and alkynes have been developed by combiningSc(OTf)3 and rhodiumcatalysis. In the absence of H2O, an endo‐cycloisomerization/CH activation cascadereaction provided 2,3‐dihydronaphtho[1,2‐b]furans in good to high yields. In the presence of H2O, the product of alkynol hydration underwent an addition/CH activation cascadereaction with an alkyne, which led
通过结合Sc(OTf)3和铑催化作用,开发了炔醇和炔烃的两个可调级联反应。在不存在H的2 O,一种内切-cycloisomerization / C ħ激活级联反应提供2,3-二氢萘并[1,2- b以良好至高产率]呋喃。在H的存在2 O,炔醇水化的产品进行加法/ C ħ激活级联与炔烃反应,从而导致4,5-二氢3的形成ħ -螺[呋喃-2,1-' [异戊烯]衍生物在温和的反应条件下收率很高。级联反应的机理研究表明,决定速率的步骤涉及CH键裂解和炔醇的水合在两个反应途径之间的转换中起关键作用。
Cascade Reaction of Alkynols and 7-Oxabenzonorbornadienes Involving Transient Hemiketal Group Directed C–H Activation and Synergistic Rh<sup>III</sup>/Sc<sup>III</sup> Catalysis
作者:Deng Yuan Li、Liang Liang Jiang、Shuang Chen、Zheng Lu Huang、Li Dang、Xin Yan Wu、Pei Nian Liu
DOI:10.1021/acs.orglett.6b02587
日期:2016.10.7
As the first cascade C–Hactivationdirected by a transient group, reaction of alkynols and 7-oxabenzonorbornadienes has been achieved via synergistic rhodium and scandium catalysis to afford spirocyclic dihydrobenzo[a]fluorenefurans. This transformation proceeds by a transient hemiketal group directedC–Hactivation, dehydrative naphthylation, and intramolecular Prins-type cyclization. Mechanistic
作为由一个瞬态基团控制的第一个级联C–H活化,炔醇与7-氧杂苯并降冰片二烯的反应已通过协同的铑和scan催化作用而得到,以提供螺环二氢苯并[ a ]芴呋喃。这种转化是通过一个半胱氨酸基团直接引导C–H活化,脱水萘化和分子内Prins型环化而进行的。机理研究和密度泛函理论计算表明,决定速率的步骤是C–H键断裂,瞬态半酮基和协同Rh III / Sc III催化均起关键作用。
Reductive Carbocyclization of Homoallylic Alcohols to <i>syn</i>
-Cyclobutanes by a Boron-Catalyzed Dual Ring-Closing Pathway
carbocyclization of homoallylic alcohols has been developed by using hydrosilanes as reducing reagents to provide a range of 1,2‐disubstituted arylcyclobutanes. The reaction proceeds in a cis‐selective manner with high efficiency under mild conditions. Mechanistic studies, including deuterium scrambling and Hammett studies, and DFT calculations, suggest a dual ring‐closing pathway.
molecules is always in demand. Oxetanes and azetidines are strained heterocycles that possess unique physicochemical properties and exhibit distinctive chemical reactivity. These together prompted us to design a novel synthetic strategy to access them through photo-catalysed annulative formal 4-endo-dig cyclization of propargylalcohols/amines with benzoquinones. This approach is devoid of any chemical
Ag-Catalyzed Selective C–C Bond Activation of Cyclopropenones to Access α-Alkylidene Lactones
作者:Shu-Lin Zhang、Zhao-Bing Wu、Chun-Xin Zhao、Yu-Xin Bai、Wei Sun、Meng Sun
DOI:10.1021/acs.orglett.4c01853
日期:2024.7.26
opening of unsymmetric cyclopropenones for the stereoselective synthesis of a diverse range of α-alkylidene lactones has been developed. In this protocol, two different C–C(O) bonds were distinguished, demonstrating selectiveC–Cbond activation. This reaction features a wide substrate scope, good functional group compatibility, and high atom economy, providing a versatile and general approach to the