一种通过连续[3 + 2]-环加成/[1,5]-σ重排和氮杂-迈克尔反应从炔基环己-2,5-二烯酮和不稳定重氮烷立体选择性合成“全中心取代”多环吡唑的有效方法被报道。所开发的过程具有高度区域选择性和立体选择性。它采用广泛的基材范围来提供结构多样的线性和桥接[4.4。 n .0]稠环吡唑,产率中等至良好。还展示了一锅法和克级合成以及合成转化。
Catalyst-Controlled Regiodivergent Alkyne Insertion in the Context of C−H Activation and Diels-Alder Reactions: Synthesis of Fused and Bridged Cycles
作者:Xukai Zhou、Yupeng Pan、Xingwei Li
DOI:10.1002/anie.201704036
日期:2017.7.3
Rhodium(III)- and cobalt(III)-catalyzed C−Hactivation of indoles and coupling with 1,6-enynes is discussed. Under rhodium(III) catalysis, the alkyne insertion follows 2,1-regioselectivity with a subsequent type-I intramolecular Diels–Alder reaction (IMDA) to afford [6,5]-fused cycles. When catalyzed by the cobalt(III) congener, 1,2-insertion of the alkyne is preferred, and followed by a rare type-II
Enantioselective Rh-Catalyzed Domino Transformations of Alkynylcyclohexadienones with Organoboron Reagents
作者:Juliane Keilitz、Stephen G. Newman、Mark Lautens
DOI:10.1021/ol400363f
日期:2013.3.1
A new enantioselective rhodium-catalyzed domino reaction is described that gives access to fused heterocycles by desymmetrization of alkyne-tethered cyclohexadienones. Two new C–C bonds and two stereocenters are formed in one step with good enantioselectivity. In contrast to prior reports, it was found that a vinylidene is not involved in the product formation but that syn-addition of the rhodium-aryl
Tunable Diastereoselective Desymmetrization of Cyclohexadienones Triggered by Copper-Catalyzed Three-Component Coupling Reaction
作者:Raghunath Reddy Anugu、Rambabu Chegondi
DOI:10.1021/acs.joc.7b00936
日期:2017.7.7
copper-catalyzed [3 + 2]-cycloaddition followed by ketenimine formation and subsequent intramolecular conjugate addition. The cascade reaction provides cis-hydrobenzofurans in good yields with excellent diastereoselectivity. The exo- or endo-selectivity of bicyclic scaffolds depends on the selection of the base in the reaction. In addition, N-tethered bicyclic products further transformed into tricyclic compounds
作者:Thi Le Nhon Nguyen、Celia A. Incerti-Pradillos、William Lewis、Hon Wai Lam
DOI:10.1039/c8cc03204a
日期:——
The enantioselective nickel-catalyzed desymmetrization of allenyl cyclohexa-2,5-dienones by reaction with arylboronic acids is described. Nickel-catalyzed arylation of the allene gives allylnickel species, which undergo cyclization by 1,4-allylation to produce hexahydroindol-5-ones and hexahydrobenzofuran-5-ones with three contiguous stereocenters in high diastereo- and enantioselectivities.
Herein we have developed the silver-catalyzed electronic- and steric-controlled intramolecular formal [2 + 2]-cycloaddition of alkyne-tethered cyclohexadienones. Substrates with electron-rich alkynes and a less hindered quaternary carbon center afford tricyclic fused cyclobutenes through 1,7-enyne cyclization. In contrast, the formation of dihydrofurans was observed from electron-deficient alkynes