described. This method provides ready access to α-chloromethyl ketones, α-bromomethylketones and α-iodomethyl ketones in moderate to high yields from simple, inexpensive starting materials. A broad substrate scope is achieved, and the reaction is compatible with various functional groups, including alkoxy, trifluoromethyl, halide, hydroxyl, cyclohexyl, and heterocyclic groups.
Highly stereoselective synthesis of (Z)-1,2-dihaloalkenes by a Pd-catalyzed hydrohalogenation of alkynyl halides
作者:Gangguo Zhu、Dongxu Chen、Yuyi Wang、Renwei Zheng
DOI:10.1039/c2cc31553j
日期:——
An unprecedented Pd-catalyzed hydrohalogenation of alkynyl halides for the regio- and stereoselective synthesis of (Z)-1,2-dihaloalkenes has been realized using [(allyl)PdCl]2 as the catalyst and cis,cis-1,5-cyclooctadiene as the ligand. The advantages of this protocol are well illustrated by the assembly of trisubstituted (Z)-enynes and multifunctional benzenes via iterative cross-coupling reactions or tandem Diels–Alder–aromatization reactions, respectively.
Hydrogen Bonding Cluster-Enabled Addition of Sulfonic Acids to Haloalkynes: Access to Both (<i>E</i>)- and (<i>Z</i>)-Alkenyl Sulfonates
作者:Xiaojun Zeng、Shiwen Liu、Zhenyu Shi、Bo Xu
DOI:10.1021/acs.orglett.6b02061
日期:2016.10.7
We developed an efficient synthesis of alkenyl sulfonates via hydrogen bonding cluster-enabled addition of sulfonic acids to haloalkynes. The reactivity of sulfonic acids could be significantly enhanced in the presence of strong hydrogen bonding donors. This metal-free method results in good chemical yields for a wide range of haloalkyne substrates and demonstrates good functional group tolerance.
Gold- or Indium-Catalyzed Cross-Coupling of Bromoalkynes with Allylsilanes through a Concealed Rearrangement
作者:M. Elena de Orbe、Margherita Zanini、Ophélie Quinonero、Antonio M. Echavarren
DOI:10.1021/acscatal.9b02314
日期:2019.9.6
The gold(I)-catalyzed reaction of bromoalkynes with allylsilanes gives 1,4-enynes in a formal cross-coupling reaction. Mechanistic studies revealed the involvement of gold(I) vinylidenes or vinylidenephenonium gold(I) cations depending on the substituent on the bromoalkyne. In the case of bromo arylalkynes, the vinylidenephenonium gold(I) cations lead to 1,4-enynes via a 1,2-aryl rearrangement. The same reactivity has been observed in the presence of InBr3.