Nickel-Catalyzed Organozinc-Promoted Carbocyclizations of Electron-Deficient Alkenes with Tethered Unsaturation
作者:John Montgomery、Eric Oblinger、Alexey V. Savchenko
DOI:10.1021/ja9702125
日期:1997.5.1
A nickel-catalyzed method for cyclizations of electron-deficient alkenes with tethered unsaturation in the presence of organozincs was developed. Considerable flexibility in the structure of each reactive component was observed. Enones, alkylidene malonates, unsaturated β-ketoesters, and nitroalkenes participated as the electron-deficient alkene; alkynes, enones, 1,3-dienes, and aldehydes participated
开发了一种镍催化的方法,用于在有机锌存在下对具有束缚不饱和度的缺电子烯烃进行环化。观察到每个反应组件的结构具有相当大的灵活性。烯酮、亚烷基丙二酸酯、不饱和β-酮酯和硝基烯烃作为缺电子烯烃参与;炔烃、烯酮、1,3-二烯和醛作为系链不饱和键参与;以及各种 sp2 和 sp3 杂化的有机锌,包括那些具有 β-氢的有机锌,作为亲核组分参与其中。底物结构、有机锌结构和配体结构都在决定产物选择性方面发挥了重要作用。具有特殊合成意义的是从普通炔烃制备 E 或 Z 三或四取代烯烃的机会。
Enantioselective Phase-Transfer-Catalyzed Synthesis of Chiral <i>N</i>-Substituted 3,3-Dinitroazetidines by Aza-Michael Reaction
作者:Hyo-Jun Lee、Chang-Woo Cho
DOI:10.1021/acs.joc.5b02124
日期:2015.11.20
An efficient and highly enantioselective phase-transfer-catalyzedaza-Michaelreaction of 3,3-dinitroazetidine, as N-centered nucleophile, to α,β-unsaturated ketones has been achieved using a quinidine-based phase-transfer catalyst (0.5–1 mol %), providing chiral N-substituted 3,3-dinitroazetidines in good yields (up to 99%) and excellent enantioselectivities (90–95% ee). This is the first example
The acylzirconocenechloridecomplex as an acyl group donor reacts with omega-unsaturated alpha,beta-enones and -ynones under Pd-Me(2)Zn(Me(2)AlCl)-catalyzed conditions to give stereoselectively bicyclo[3.3.0] compounds through (i) formation of a Pd(II) intermediate by an oxidative addition of the Pd(0) catalyst to an enone function, (ii) cyclization of the Pd intermediate to an omega-unsaturated group