Nitration of Silyl Allenes To Form Functionalized Nitroalkenes
摘要:
An efficient nitration of silyl allenes with nitrogen dioxide radical, generated from NaNO2 and AcOH, to form alpha-nitro-alpha,beta-unsaturated silyl oximes has been developed. A similar nitration could be achieved by using Fe(NO3)(3)center dot 9H(2)O and FeCl3 center dot 6H(2)O, but different from the regioselective oxime formation, two regioisomeric chloride-trapped products were isolated with varying ratios depending on the steric bulk of the silyl group. A novel ring-closure reaction of alpha-nitro-alpha,beta-unsaturated silyl oximes upon treating with TBAF to form isooxazolidinone derivatives was also developed.
Facile Alder-Ene Reactions of Silylallenes Involving an Allenic C(sp<sup>2</sup>)H Bond
作者:Venkata R. Sabbasani、Genping Huang、Yuanzhi Xia、Daesung Lee
DOI:10.1002/chem.201503243
日期:2015.11.23
involving the activation of an allenic C(sp2)H over an allylic C(sp3)Hbond is described. In this ene reaction, the presence of a silyl substituent was found to be critical for the observed reactivity and selectivity since the corresponding alkyl‐substituted allenes show different reaction profiles. Computational studies show that the origin of this unusualreactivity is the lower bond dissociation
Divergent gold-catalysed reactions of cyclopropenylmethyl sulfonamides with tethered heteroaromatics
作者:Melanie A. Drew、Sebastian Arndt、Christopher Richardson、Matthias Rudolph、A. Stephen K. Hashmi、Christopher J. T. Hyland
DOI:10.1039/c9cc06241f
日期:——
Cyclopropenylmethyl sulfonamides with tethered heteroaromatics have been demonstrated to undergo divergent gold-catalysed cyclisation reactions. A formal dearomative (4+3) cycloaddition takes place with furan-tethered substrates, yielding densely functionalised 5,7-fused heterocycles related to the bioactive curcusone natural products. Indole-tethered substrates display divergent reactivity giving
Oxidative Dimerization of Silylallenes via Activation of the Allenic C(<i>sp</i><sup>2</sup>)–H Bond Catalyzed by Copper(I) Chloride and <i>N</i>-Hydroxyphthalimide
作者:Venkata R. Sabbasani、Daesung Lee
DOI:10.1021/acs.orglett.5b02433
日期:2015.10.2
Novel oxidativedimerization of silylallenes is described. Treatment of silylallenes with a catalytic amount of copper(I) chloride, a substoichiometric amount of N-hydroxyphthalamide, and a stoichiometric amount of a terminal oxidant diacetoxyiodobenzene afforded head-to-head dimers as the main products. Silyallenes containing a small ring afforded only dimers, whereas as the ring size increased 1