Radical-nucleophilic substitution (SRN1) reactions. Part 7. Reactions of aliphatic α-substituted nitro compounds.
作者:Suleiman I. Al-Khalil、W. Russell Bowman、Katherine Gaitonde、Madeleine A. Marley (née Nagel)、Geoffrey D. Richardson
DOI:10.1039/b103350f
日期:——
α-Nitrothiocyanates R2C(SCN)NO2 have been prepared by oxidative addition of thiocyanate anion to nitronate anions and undergo SRN1 substitution reactions by loss of thiocyanate with nitronate anions, phenylsulfinate, azide and p-nitro- and p-chloro-benzenethiolates in dipolar aprotic solvents. 2-Nitro-2-thiocyanatopropane and other 2-substituted-2-nitropropanes [Me2C(X)NO2 with X = I, Br, Cl, NO2, PhSO2] react with thiolates by SRN1 reactions and/or redox reactions to give disulfides by a polar abstraction or chain SET (SET2) mechanisms. The products are dependent on the nucleophilicity of the thiolates, the polarisability of the α-substituent, the solvent and the presence of light catalysis, radical traps or strong electron acceptors. 2-Substituted-2-nitropropanes [Me2C(X)NO2 with X = N3,
NO2, CN, p-NO2âC6H4âNN] undergo SRN1 substitutions with thiolates by loss of nitrite. 2-Substituted-2-nitropropanes Me2C(X)NO2 and thiolates only yield disulfides in methanol due to solvation of the nitro groups.
Radical-nucleophilic substitution (SRN1) reactions of α-nitro-thiocyanates
作者:Suleiman I. Al-Khalil、W.Russell Bowman
DOI:10.1016/s0040-4039(00)81970-x
日期:1983.1
α-Nitro-thiocyanates undergo substitution by a SRN1mechanism with a range of anions to give loss of thiocyanate, corroborating behaviour observed for the intermediate α-nitro-thiocyanato radical-anions by e.s.r. spectroscopy.
A catalytic enantioselective approach to tetrol bearing vicinal all-carbon quaternary stereogenic centers
作者:Hui Yang、Kou-Sen Cao、Wen-Hua Zheng
DOI:10.1039/c7cc00457e
日期:——
The first highly enantioselectivecatalytic protocol for selective manipulation of tetrol benzylidene acetals through chiral phosphoric acid mediated oxidative desymmetrization is reported. This efficient approach provides a general access to...