The BF3-catalyzed decomposition of m- and p-substituted α-diazoacetophenones in excess of methyl thiocyanate and ethyl thiocyanate gave the corresponding 2-methylthio-, and 2-ethylthio-5-aryloxazoles, respectively in good yields along with s-alkyl-n-aroylmethylthiocarbamates and α-ethoxyacetophenones. However, yields of 2-dimethylamino-5-aryloxazoles by the reaction of dimethylcyanamide with α-diazoacetophenones
Unified Synthesis of Azepines by Visible-Light-Mediated Dearomative Ring Expansion of Aromatic <i>N</i>-Ylides
作者:Matthew J. Mailloux、Gabrielle S. Fleming、Shruti S. Kumta、Aaron B. Beeler
DOI:10.1021/acs.orglett.0c04050
日期:2021.1.15
unified approach to azepines by dearomative photochemical rearrangement of aromatic N-ylides. Deprotonation of quaternary aromatic salts with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or N,N,N′,N’-tetramethylquanidine (TMG) under visible light irradiation provides mono- and polycyclic azepines in yields up to 98%. This ring-expansion presents a new mode of access to functionalized azepines from N-heteroarenes
Copper-dppf catalyzed reductive coupling of diazo compounds through terminal nitrogen is reported. However, copper catalysts are known to produce carbene from diazo compounds; the reaction conditions played an important role in the formation of diazine over carbene generation. Several control experiments have been conducted to understand the reaction mechanism and found that the formation of a copper–Mg
Catalytic cross-coupling of diazo compounds with coinage metal-based catalysts: an experimental and theoretical study
作者:Ivan Rivilla、W. M. C. Sameera、Eleuterio Alvarez、M. Mar Díaz-Requejo、Feliu Maseras、Pedro J. Pérez
DOI:10.1039/c2dt32439c
日期:——
We examined the ability of TpxM (Tpx = hydrotris(pyrazolyl)borateligand; M = Cu and Ag) and IPrMCl (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene; M = Cu, Ag, Au) complexes as catalyst precursors for the cross-coupling of diazo compounds. Experimental data showed that the metal centre can be tuned with the appropriate selection of the ligand to yield either the homo- or hetero-coupling (cross-coupling)
我们检查了Tp x M(Tp x =氢三(吡唑基)硼酸酯配体; M =铜和银)和IPrMCl(IPr = 1,3-双(二异丙基苯基)咪唑-2-亚基; M = Cu,Ag, Au)络合物作为重氮化合物交叉偶联的催化剂前体。实验数据表明,该金属中心可以与配体的适当的选择,以产生任一同源或异源偶联(交叉耦合)的产品来调整。通过对反应机理的计算研究,合理化了实验反应模式,并确定了控制选择性的关键反应步骤:金属碳烯中间体与一种重氮化合物之间的初始反应。