Intramolecular ipso-Halocyclization of 4-(p-Unsubstituted-aryl)-1-alkynes Leading to Spiro[4,5]trienones: Scope, Application, and Mechanistic Investigations
摘要:
A new, general method for the synthesis of spiro[4,5]trienores is described by the intramolecular ipso-halocyclization of 4-(p-unsubstituted-aryl)-1-alkynes. In the presence of halide electrophiles, a variety of 4-(p-unsubstituted-aryl)-1-alkynes underwent the intramolecular ipso-halocyclization with water smoothly, affording the corresponding halo-substituted spiro[4,5]trienones in moderate to good yields. The obtained spiro[4,5]trienones can be applied in constructing the azaquaternary tricyclic skeleton via Pd-catalyzed Heck reaction. Notably, the prepared spiro[4,5]trienones and azaquaternary tricycles are of importance in the areas of pharmaceuticals and agrochemicals. The mechanism of the intramolecular ipso-halocyclization reaction is also discussed according to the O-18-labeling experiments and DFT calculations.
Transformations of N-arylpropiolamides to indoline-2,3-diones and acids via C≡C triple bond oxidative cleavage and C(sp2)–H functionalization
作者:Ming-Bo Zhou、Yang Li、Xuan-Hui Ouyang、Jin-Heng Li
DOI:10.1007/s11426-019-9633-x
日期:2020.2
A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described, which is promoted by a cooperative action of catalytic CuBr2, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and O2. The method provides a practical tool for transformations of alkynes by means of a C–H
3,4-Fused tricyclic indole scaffolds are ubiquitous in bioactive natural products and pharmaceuticals. A new protocol for the synthesis of 3,4-fused tricyclic indoles has been developed throughcascade carbopalladation and C–H amination with N,N-di-tert-butyldiaziridinone. The protocol allows access to a range of 3,4-fused tricyclic indoles, including those containing various linkers and fused with
Palladium-Catalyzed <i>anti</i>-Carbosilylation of Alkynes to Access Isoquinolinone-Containing Exocyclic Vinylsilanes
作者:Cang Cheng、Yanghui Zhang
DOI:10.1021/acs.orglett.1c01931
日期:2021.8.6
developed. The trans-vinylpalladium species, generated through intramolecular syn-carbopalladation of alkynes and subsequent cis-trans isomerization, were captured by hexamethyldisilane to form multisubstituted vinylsilanes. This reaction provides a useful strategy for the stereoselective synthesis of isoquinolinone-containing exocyclic tetrasubstituted vinylsilanes.
Intermolecular C–H silylation through cascade carbopalladation and vinylic to aryl 1,4-palladium migration
作者:Cang Cheng、Qiongqiong Zhu、Yanghui Zhang
DOI:10.1039/d1cc03677g
日期:——
A palladium-catalyzed remote C–H silylation reaction has been developed through vinylic to aryl 1,4-palladium migration. By using alkyne-tethered aryliodides as the starting materials and hexamethyldisilane as the silylating reagent, the reaction involves cascade intramolecular carbopalladation, 1,4-palladium migration, and silylation with hexamethyldisilane, and leads to the formation of exocyclic
Metal-Free Oxidative <i>Ipso</i>-Carboacylation of Alkynes: Synthesis of 3-Acylspiro[4,5]trienones from <i>N</i>-Arylpropiolamides and Aldehydes
作者:Xuan-Hui Ouyang、Ren-Jie Song、Yang Li、Bang Liu、Jin-Heng Li
DOI:10.1021/jo5005982
日期:2014.5.16
A general and metal-free radical route to synthesis of 3-acylspiro[4,5]trienones is established that utilizes TBHP (tert-butyl hydrogenperwdde) as an oxidation and a reaction partner to trigger the oxidative ipso-carboacylation of N-arylpropiolamides with aldehydes. This method offers a new difunctionalization of alkynes through oxidative cross coupling of the aldehyde C(sp(2))-H bond with an ipso-aromatic carbon.