Reaction of aromatic acetyl derivatives with benzyltrimethylammonium dichloroiodate in refluxing dichloroethane/methanol for several hours gave α-chloroacetyl derivatives in good yields.
Abstract A practical synthesis of α-bromo/iodo/chloroketones fromolefins under visible-light irradiation conditions has been developed. In the presence of PhI(OAc)2 as promoter and under ambient conditions, the reactions of styrenes and triiodomethane undergo the transformation smoothly to deliver the corresponding α-iodoketones without additional photocatalyst in good yields under sunlight irradiation
An operationally simple and safe synthesis of α‐haloketones using KBr and KCl as nonhazardous halogen sources is reported. It involves an iron‐catalysed reaction of alkenes with KBr/KCl using O2 as terminal oxidant under the irradiation of visible‐light. This strategy avoids the risks associated with handling halo‐contained electrophiles (Cl2, Br2, NCS, NBS). The process is tolerant to several functional
N-Heterocyclic Carbene Catalyzed Switchable Reactions of Enals with Azoalkenes: Formal [4 + 3] and [4 + 1] Annulations for the Synthesis of 1,2-Diazepines and Pyrazoles
作者:Chang Guo、Basudev Sahoo、Constantin G. Daniliuc、Frank Glorius
DOI:10.1021/ja510737n
日期:2014.12.17
A regio- and enantioselective formal [4 + 3] annulation reaction between enals and in situ formed azoalkenes has been achieved. A diverse set of 1,2-diazepine derivatives were synthesized in good yields with excellent enantioselectivities (often 99% ee). Alternatively, modifying the standard NHC catalyst switched the reactivity toward a formal [4 + 1] annulation to afford functionalized pyrazoles. The
Asymmetric organocatalytic Michael/α-alkylation reaction of α,β-unsaturated aldehyde with chloroacetophenone
作者:Wenjun Li、Xin Li、Tingting Ye、Wenbin Wu、Xinmiao Liang、Jinxing Ye
DOI:10.1016/j.tetlet.2011.03.079
日期:2011.5
Asymmetricorganocatalytic Michael/α-alkylation reactions of α,β-unsaturatedaldehydes with chloroacetophenones have been developed. The biologically useful cyclopropane motifs were synthesized with high yields and up to >99% ee, >30:1 dr through Jørgensen–Hayashi catalyst under mild conditions.