Direct Synthesis of γ‐Keto Sulfones from Allylic Alcohols: One‐Pot Palladium(II)‐Catalyzed Generation of Enones Followed by Water‐Mediated 1,4‐Addition of Organosulfinates
作者:Mari Vellakkaran、Murugaiah M. S. Andappan、Kommu Nagaiah、Jagadeesh Babu Nanubolu
DOI:10.1002/ejoc.201600494
日期:2016.7
which indicated a chemoselective catalytic system for the preparation of halogen-bearing γ-keto sulfones. This one-pot method does not require an acid, a base, or isolation of any intermediate. Control experiments indicated that the active catalyst of the first step also promoted the subsequent C–S bond-formation reaction. Water was found to accelerate the reaction rate and to be involved in the protonolysis
A series of highly strained bicyclo[3.n.1]alkenones have been successfully constructed in good-to-excellent enantioselectivities and moderate-to-good yields via copper-catalyzed formal [3+3] cycloaddition. The versatile chiral cycloadducts could be selectively converted into various valuable bridge systems, which hold considerable potential for the construction of natural and bioactive compounds containing
ketones using Koser’s hypervalent iodine reagent is reported. A variety of acyloxy groups from long-chain aliphatic, aromatic, α,β-unsaturated carboxylic acids have been installed efficiently for the first time. The oxyacylated adducts were used for the preparation of densely functionalized chiral δ-lactones and cyclopentenes using carbene organocatalysis.
Organocatalytic β-Azidation of Enones Initiated by an Electron-Donor–Acceptor Complex
作者:Rajendra P. Shirke、S. S. V. Ramasastry
DOI:10.1021/acs.orglett.7b02861
日期:2017.10.6
β-unsaturated ketones is described. Reaction of the Zhdankin azidoiodane with enones in the presence of a catalytic amount of an amine provides β-azido ketones via the formation of an electron-donor–acceptor complex. The application of this protocol is demonstrated through one-step elaborations leading to the synthesis of unprecedented classes of 1,2,3-triazoles.
An unprecedented N-heterocyclic carbene (NHC)-catalyzed enantioselective [3 + 2] annulation of enals with vinyl ketones has been achieved. Unlike chalcones, the β-unsubstituted enones, namely, vinyl ketones, have remained challenging in terms of reactivity, especially enantioselectivity. The disubstituted cyclopentenes were obtained in good yields and excellent stereoselectivities in the presence of