Ring Contraction of α,β-Unsaturated Cyclic Amines with cis-Dihydroxylation at the α,β-Position
摘要:
alpha,beta-Unsaturated cyclic amines are oxidized by OsO(4) to afford alpha,beta-cis-dihydroxylated compounds which are thermodynamically transformed into ring-opened keto-alcohols. The keto-alcohols are then cyclized to form synthetically useful ring-contracted cyclic amines.
Construction of Nitrogen-Fused Tetrahydroquinolines via a Domino Reaction
摘要:
An efficient domino approach for the diastereoselective synthesis of polyfunctionalized nitrogen-fused tetrahydroquinoline frameworks under mild conditions has been developed. The scope and limitation of this transformation were investigated by using a range of readily accessible enamides and benzyl azides. This method is also applicable to the formation of 2,3-functionalized enamides.
Herein the first example of the iron(II)‐catalyzed trifluoromethylation of enamide using mild and simple reaction conditions is reported. The method is cost‐effective and uses the easy‐to‐handle Togni’s reagent as the electrophilic CF3 source. This transformation is totally regioselective at the C3 position of enamides and exhibits broad substrate scope, good functional group tolerance and thus demonstrates
An efficient Pd-catalyzed decarboxylative cross-coupling reaction of simple enamides was achieved. Depending on the choice of the nitrogen-protecting group, a site-selective synthesis of mono- or diarylated framework(s) was performed under mild conditions. This unprecedented reactivity could be applied to the synthesis of a range of 2- or 2,4-diarylated nitrogen-containing bioactive derivatives.
convenient method for the copper(II)-catalyzed direct arylation of cyclic and nonaromatic enamides using diaryliodoniumsalts has been developed. The reaction demonstrates large functional group tolerance, good yields, and total regioselectivity with a C(3)-functionalization. The synthetic potential of this coupling was explored by using a range of readily accessible diaryliodoniumsalts and enamides.
Carbene Reactions of α-Oxacyclo- and α-Azacyclo-N-aziridinylimines: Effect of Heteroatom and Ring Size in the Ring Expansion Reaction
作者:Sunggak Kim、Joo-Yong Yoon
DOI:10.1055/s-2000-7598
日期:——
Carbenes, generated from thermolysis of α-oxacyclo- and α-azacyclo-N-aziridinylimines in refluxing toluene, underwent ring expansions via insertion of alkyl carbenes into carbon-carbon bonds and intramolecular ammonium ylide formations, respectively. Ring expansion reaction of α-oxetanyl-N-aziridinylimines occurred via alkylidenecarbene intermediates, whereas thermal reaction of α-azetidinyl-N-aziridinylimines afforded α-aminoacetylene compounds via 1,2-H migration of alkylidenecarbene intermediates.
Catalytic Desaturation of Aliphatic Amides and Imides Enabled by Excited-State Base-Metal Catalysis
作者:Chenyang Wang、Luis Miguel Azofra、Phong Dam、Michael Sebek、Norbert Steinfeldt、Jabor Rabeah、Osama El-Sepelgy
DOI:10.1021/acscatal.2c01723
日期:2022.8.5
Herein, we report a photoexcited base-metal-catalyzed selective desaturation of aliphaticamides and imides. The reaction is catalyzed by a base-metal cobalt complex under visible-light irradiation. This transformation can be efficiently processed at room temperature and enables the synthesis of valuable cyclic and acyclic enamides and enimides from abundant chemicals. Density functional theory (DFT)