Para-coupling of phenols with C2/C3-substituted benzothiophene S-oxides
作者:Zhen He、Tony Biremond、Gregory J.P. Perry、David J. Procter
DOI:10.1016/j.tet.2020.131315
日期:2020.12
C2 and C3 substituted benzothiophenes are common structures in medicinal and materials chemistry. The cross-coupling of phenols with benzothiophenes is a useful route towards these important molecules. In this report we reveal an efficient C–H/C–H-type cross-coupling of benzothiophenes, activated as their S-oxides, with phenols to give C2/C3 arylated benzothiophenes. Whereas previous reports describe
Chiral Benzothiophene Synthesis via Enantiospecific Coupling of Benzothiophene S‐Oxides with Boronic Esters
作者:Ruocheng Sang、Adam Noble、Varinder K. Aggarwal
DOI:10.1002/anie.202112180
日期:2021.11.22
The C2 alkylation of functionalized benzothiophenes has been explored. Enantiospecific C−C bond formation is achieved via O-activation and 1,2-metalate shift of benzothiophene S-oxide boronate complexes, which enables expedient access to chiral C2-alkylated benzothiophenes.
Synthesis of C2 Substituted Benzothiophenes via an Interrupted Pummerer/[3,3]-Sigmatropic/1,2-Migration Cascade of Benzothiophene <i>S</i>
-Oxides
作者:Zhen He、Harry J. Shrives、José A. Fernández-Salas、Alberto Abengózar、Jessica Neufeld、Kevin Yang、Alexander P. Pulis、David J. Procter
DOI:10.1002/anie.201801982
日期:2018.5.14
Functionalized benzothiophenes are important scaffolds found in molecules with wide ranging biological activity and in organic materials. We describe an efficient, metal‐free synthesis of C2 arylated, allylated, and propargylated benzothiophenes. The reaction utilizes synthetically unexplored yet readily accessible benzothiophene S‐oxides and phenols, allyl‐, or propargyl silanes in a unique cascade
of N,α-diphenyl nitrone have been investigated in the 2- or 3-substituted (methyl, phenyl, chloro, bromo, piperidino, acetyl) benzo[b]thiopheneS-oxide and SS-dioxide series. The S-oxide and SS-dioxide derivatives show the same ability to form adducts. The 2,3-dihydrobenzo[b]-thieno[2,3-d]isoxazolidines are generally formed only as a single regioisomer, except in the case of 2-methyl dipolarophiles
已经研究了N,α-二苯基硝酮的1,3-偶极环加成反应是在2-或3-取代的(甲基,苯基,氯,溴,哌啶子基,乙酰基)苯并[ b ]噻吩S-氧化物和SS-二氧化物系列中进行的。 。该小号氧化物和SS二氧化物衍生物显示出,以形成加合物的能力相同。2,3-二氢苯并[ b ]-噻吩[2,3- d]异恶唑烷通常仅以单一的区域异构体形式形成,除了2-甲基双极性亲和剂形成两个区域异构体的情况以外。在CNDO / S计算和光电光谱电离势的基础上,根据边界轨道相互作用来讨论区域选择性。具有肘形形状的硝酮可能导致非对映异构体的形成,但实际上仅形成了反式-异恶唑烷。S-氧化物系列中的立体选择性较低,因为我们仅与3-甲基双极性亲和剂获得一种加合物,但与3-苯基衍生物同时获得了顺式和反式表位。溴衍生物不导致任何加合物。X给出了两种加合物的-射线结构,其对应于将硝基添加至苯并[ b ]噻吩SS-二氧化物和2-甲基衍生物。
Isoxazolines by cycloadditions of mesitonitrile oxide with benzo[b]thiophene S-oxide and S,S-dioxide. Structural studies, theoretical explanations, and kinetics