Metal Carbene-Promoted Sequential Transformations for the Enantioselective Synthesis of Highly Functionalized Cycloheptadienes
摘要:
A two-step, three-component coupling of an alkyne, enol ether, and vinyl diazoester was accomplished by use of successive metal carbene-catalyzed transformations. This efficient approach to cycloheptadienes is both diastereo- and enantioselective. Kinetic resolution was accomplished on dienol ethers bearing a racemic chiral center at the propargylic position. A model is offered which explains the observed selectivity and accounts for the reactivity difference between trans- and cis-dienol ethers.
Gold-catalyzed reactions of propargylic esters with vinylazides for the synthesis of Z- or E-configured buta-1,3-dien-2-yl esters
作者:Sachin Bhausaheb Wagh、Rai-Shung Liu
DOI:10.1039/c5cc05945c
日期:——
Gold-catalyzed synthesis of buta-1,3-dien-2-yl esters by the reaction of propargyl esters with vinylazides is described; the reaction mechanism is postulated to involve a vinyl attack of vinylazides at alkenyl gold carbenes.
Rhodium-catalysed synthesis of fused pyrimidine derivatives employing N-sulfonyl-1,2,3-triazoles as a 1-aza-[4C] synthon
作者:Ze-Feng Xu、Yuehui An、Yidian Chen、Shengguo Duan
DOI:10.1016/j.tetlet.2019.06.023
日期:2019.7
A new synthetic application of N-sulfonyl-1,2,3-triazoles acting as a 1-aza-[4C] synthon via the 1,2-shift reaction of an α-imine rhodium carbene was developed for the synthesis of fused pyrimidine derivatives. The high reactivity of the strained three-membered 2H-azirine ring facilitated the unusual cyclization of electron-deficient dienes with electron-deficient dienophiles. The compatibility was
Palladium-Catalyzed Ring-Opening Alkynylation of Cyclopropenones
作者:Takanori Matsuda、Yusuke Sakurai
DOI:10.1002/ejoc.201300220
日期:2013.7
N-Heterocyclic carbene–palladium catalysts are used to promote addition/ring opening of cyclopropenones with terminal alkynes. The ring-opening alkynylation affords alkenyl alkynyl ketones in good yields. For reactions with propargylic esters having an aryl or alkenyl substituent at the propargylic position, [3+2] annulation occurs exclusively to give 4-methylenecyclopentenones.
and limitations of the copper-catalyzedpropargylicamination of various propargylic esters with amines are presented, where optically active diphosphines such as Cl-MeO-BIPHEP and BINAP work as good chiral ligands. A variety of secondary amines are available as nucleophiles for this catalytic reaction to give the corresponding propargylic amines with a high enantioselectivity. The results of some stoichiometric
The highly enantioselective copper-catalyzed propargylic amination of propargylic esters with amine hydrochloride salts has been realized for the first time using copper salts with chiral N,N,P-ligands. This method features a broad substrate scope and wide functional group tolerance, generating propargylic amines in good to excellent yields with high enantioselectivities (up to 99% ee). The utility