saturated oxygenheterocycles, providing an efficient method for the synthesis of 3-haloacrylates. The ring-opening reaction enables the construction of two C–X (X = Cl, Br, or I) bonds and a C–O bond as well as the cleavage of two C–O bonds and a C–C bond in a single step. This protocol is highly atomeconomical, has an excellent substrate scope, and exhibits the ability for gram-scale reaction.
A highly efficient method is disclosed for the synthesis of 1,2-dichalcogen heterocycles via [3 + 2] cycloaddition of cyclopropenone derivatives and elemental chalcogens. Different from other cyclopropenone derivatives, cyclopropenselenones undergo unprecedented rearrangement with elemental sulfur. The features of this protocol include mild reaction conditions, high efficiency, excellent atom economy
Thermally Induced Tandem Cycloaddition of 2-Alkyl-3-phenylcyclopropenones to 6-Aryl-1,5-diazabicyclo[3.1.0]hexanes
作者:A. P. Molchanov、D. I. Sipkin、Yu. B. Koptelov、R. R. Kostikov
DOI:10.1007/s11178-005-0205-z
日期:2005.4
Thermolysis of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes in the presence of 2-alkyl-3-phenylcyclopropenones gives fused polycyclic systems of the 4a,7b-diazacyclopenta[cd]inden-7-one series as a result of addition of two cyclopropenone molecules and extrusion of CO molecule. The first step of the process is characterized by 100% regioselectivity, leading to the adduct with vicinal arrangement of the aryl groups, while the regioselectivity of the second step is likely to be determined by spatial interactions between substituents in the cyclopropenone molecule and trimethylene bridge of the diazabicyclohexane. Steric hindrances in the second step could eliminate formation of stable products.
6- 芳基-1,5-二氮杂双环[3.1.0]己烷在 2-烷基-3-苯基环丙烯酮存在下发生热解,产生 4a,7b-二氮杂环戊并[cd]茚-7-酮系列的融合多环体系,这是两个环丙烯酮分子相加和 CO 分子挤出的结果。该过程第一步的特点是具有 100% 的区域选择性,可产生芳基邻接排列的加合物,而第二步的区域选择性可能取决于环丙烯酮分子中的取代基和二氮杂双环己烷的三亚甲基桥之间的空间相互作用。第二步中的立体阻碍可能会导致无法形成稳定的产物。
Nickel(0)‐Catalyzed Enantioselective [3+2] Annulation of Cyclopropenones and α,β‐Unsaturated Ketones/Imines
作者:Dachang Bai、Yanjiang Yu、Haiming Guo、Junbiao Chang、Xingwei Li
DOI:10.1002/anie.201913130
日期:2020.2.10
Ni0 -catalyzed chemo- and enantioselective [3+2] cycloaddition of cyclopropenones and α,β-unsaturatedketones/imines is described. This reaction integrates C-C bond cleavage of cyclopropenones and enantioselective functionalization by carbonyl/imine group, offering a mild approach to γ-alkenyl butenolides and lactams in excellent enantioselectivity (88-98 % ee) through intermolecular C-C activation