Electrophilic Reactions of Carbenoids. Synthesis of Fused Heterocyclic Systems via Intramolecular Nucleophilic Substitution of Carbenoids
摘要:
Intramolecular nucleophilic substitution of carbenoids with oxygen, nitrogen, and sulfur nucleophiles leading to the synthesis of fused heterocyclic compounds has been studied. For the purpose of this investigation styryl type gem-dihalides 4, 8, 18, 20, 28 containing a nucleophilic substituent in the ortho position of the aromatic ring have been synthesized. Carbenoids have been generated in those systems by the halogen-metal exchange reaction and shown to readily undergo intramolecular nucleophilic substitution by the properly located nucleophilic group (OH, SH, or NH2). As a result a new synthetic route to benzofurans, thianaphthenes, and indoles has been established based on nucleophilic substitution of vinyl halides by an ortho substituent. The dramatic increase of reactivity of vinyl halides upon introduction of lithium has been explained as being due to metal-assisted ionization.
Electrophilic Reactions of Carbenoids. Synthesis of Fused Heterocyclic Systems via Intramolecular Nucleophilic Substitution of Carbenoids
作者:Marek Topolski
DOI:10.1021/jo00122a046
日期:1995.9
Intramolecular nucleophilic substitution of carbenoids with oxygen, nitrogen, and sulfur nucleophiles leading to the synthesis of fused heterocyclic compounds has been studied. For the purpose of this investigation styryl type gem-dihalides 4, 8, 18, 20, 28 containing a nucleophilic substituent in the ortho position of the aromatic ring have been synthesized. Carbenoids have been generated in those systems by the halogen-metal exchange reaction and shown to readily undergo intramolecular nucleophilic substitution by the properly located nucleophilic group (OH, SH, or NH2). As a result a new synthetic route to benzofurans, thianaphthenes, and indoles has been established based on nucleophilic substitution of vinyl halides by an ortho substituent. The dramatic increase of reactivity of vinyl halides upon introduction of lithium has been explained as being due to metal-assisted ionization.
Efficient Synthesis of Benzothiophenes by an Unusual Palladium-Catalyzed Vinylic CS Coupling
作者:Christopher S. Bryan、Julia A. Braunger、Mark Lautens
DOI:10.1002/anie.200902843
日期:2009.9.7
construction of a CS and a CC bond under catalytic conditions forms the basis of an efficient route to diversely functionalized benzothiophenes from gem‐dihalovinyl thiophenols. The CC bond can be formed in this tandem catalytic process with an organoboron reagent as shown in the scheme (R1=H, Me, F, Cl, Br, OCH2O; R2=H, Me; R3=aryl, heteroaryl, alkenyl, alkyl), or by Heck or Sonogashira coupling with an
同时施工一个C S和一个C 催化条件下C键形成从不同地官能化的苯并噻吩的高效路由的基础宝石-dihalovinyl苯硫酚。与c 可以在此串联与有机硼试剂催化工艺来形成C键为显示在方案(R 1 = H中,Me,F,氯,溴, OCH 2 ö ; R 2 = H中,Me; R 3=芳基,杂芳基,烯基,烷基),或通过Heck或Sonogashira与烯烃或炔烃偶联。