Cyclic Alkenylsulfonyl Fluorides: Palladium‐Catalyzed Synthesis and Functionalization of Compact Multifunctional Reagents
作者:Terry Shing‐Bong Lou、Scott W. Bagley、Michael C. Willis
DOI:10.1002/anie.201910871
日期:2019.12.19
A series of low-molecular-weight, compact, and multifunctional cyclic alkenylsulfonyl fluorides were efficiently prepared from the corresponding alkenyl triflates. Palladium-catalyzed sulfur dioxide insertion using the surrogate reagent DABSO effects sulfinateformation, before trapping with an F electrophile delivers the sulfonyl fluorides. A broad range of functional groups are tolerated, and a correspondingly
Palladium-Catalyzed Synthesis of Ammonium Sulfinates from Aryl Halides and a Sulfur Dioxide Surrogate: A Gas- and Reductant-Free Process
作者:Edward J. Emmett、Barry R. Hayter、Michael C. Willis
DOI:10.1002/anie.201404527
日期:2014.9.15
range of useful molecules and materials, and despite a variety of preparative methods being available, processes which introduce the most basic sulfonyl building block, sulfurdioxide, using catalytic methods, are rare. Described herein is a simple reaction system consisting of the sulfurdioxide surrogate DABSO, triethylamine, and a palladium(0) catalyst for effective convertion of a broad range of
Electrochemical oxidation of triphenylphosphine in the presence of allylsilanes: Voltammetric studies and regioselective preparation of allyltriphenylphosphonium salts.
Electrochemical oxidation of triphenylphosphine (1) in dichloromethane containing allylsilanes (2) in an undivided cell afforded allyltriphenylphosphonium salts (3). The addition of 1 to 2 took place exclusively at the γ-position of 2 and the reaction was extended to provide a convenient method for the synthesis of cyclic phosphonium salts (3) bearing β-exo-methylene. The yields of 3 depended on the cathode material : use of a lead cathode, which has a high hydrogen overpotential, gave favorable results. Based on the results of the voltammetric study, the process of formation of 3 is suggested to involve electrophilic attack of the triphenylphosphine radical cation on 2 as the key step.
Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates
作者:Wengang Xu、Naohiko Yoshikai
DOI:10.3762/bjoc.14.60
日期:——
A cobalt-N-heterocycliccarbene (NHC) catalyst efficiently promotes an ortho C-Halkenylation reaction of pivalophenone N-H imine with an alkenylphosphate. The reaction tolerates various substituted pivalophenone N-H imines as well as cyclic and acyclic alkenylphosphates.
synthetically useful approach to functionalized triazoles is described via the reaction of β-carbonyl phosphonates and azides. 1,4- and 1,5-disubstituted and 1,4,5-trisubstituted triazoles can be regio- and chemoselectively accessed under mild conditions in good to excellent yields (31 examples, up to 99%). A mechanism is proposed that rationalizes the avoidance of the 4-phosphonate byproducts, which