A 1,4‐Palladium Migration/Heck Sequence with Unactivated Alkenes: Stereoselective Synthesis of Trisubstituted 1,3‐Dienes
作者:Ze‐Jian Xue、Meng‐Yao Li、Bin‐Bin Zhu、Zhi‐Tao He、Chen‐Guo Feng、Guo‐Qiang Lin
DOI:10.1002/adsc.202001589
日期:2021.4.13
The palladium‐catalyzedcross‐coupling of ortho‐vinyl aromatic bromides and olefins was achieved through a controllable 1,4‐palladium migration/Heck cascade protocol. The reaction represents a mild, efficient and highly stereoselective method for the synthesis of trisubstituted 1,3‐dienes, especially for triaryl‐substituted ones.
Highly Stereoselective Synthesis of 1,3-Dienes through an Aryl to Vinyl 1,4-Palladium Migration/Heck Sequence
作者:Tian-Jiao Hu、Meng-Yao Li、Qian Zhao、Chen-Guo Feng、Guo-Qiang Lin
DOI:10.1002/anie.201801963
日期:2018.5.14
An efficient aryl to vinyl 1,4‐palladium migration/Heck sequence was developed for the stereoselectivesynthesis of 1,3‐dienes. High stereoselectivity was observed not only for 1,3‐dienes bearing two similar aryl groups at terminal positions, but also for those with configurations shown to be unfavorable with previous methods.
Asymmetric Alkenylation of Enones and Imines Enabled by A Highly Efficient Aryl to Vinyl 1,4-Rhodium Migration
作者:Shu-Sheng Zhang、Tian-Jiao Hu、Meng-Yao Li、Yi-Kang Song、Xiao-Di Yang、Chen-Guo Feng、Guo-Qiang Lin
DOI:10.1002/anie.201813585
日期:2019.3.11
The asymmetricrhodium‐catalyzed alkenylation of enones and imines with arylboronic acids has been developed. A highly controllable aryl to vinyl 1,4‐rhodium migration is the key step. Stereodefined vinyl moieties were installed in excellent enantioselectivies for most examined examples. DFT calculations reveal that the driving force of this rhodium migration is a kinetically favored process.
Synthesis of 1(3<i>H</i>)-Imino-2-benzothiophene and 1-Imino-1<i>H</i>-2-benzothiopyran Derivatives by Reactions of Secondary<i>o</i>-(Vinyl)thiobenzamide Derivatives with Iodine
Efficient methods have been developed for the preparation of 1(3H)-imino-2-benzothiophene and 1-imino-1H-2-benzothiopyran derivatives. Treatment of secondary o-(vinyl)thiobenzamide derivatives with iodine in the presence of sodium hydrogencarbonate in acetonitrile at 0 °C gave the former derivatives. Similar treatment at reflux gave the latter derivatives.
Hydriodic Acid-Mediated Cyclization of α-Substituted Secondary 2-Ethenylbenzamides: Synthesis of 2-Substituted 2,3-Dihydro-3,3-dimethyl-1H-isoindol-1-ones and 3,3-Disubstituted (E)-1-(Arylimino)-1,3-dihydroisobenzofurans
for the preparation of 2‐substituted 2,3‐dihydro‐3,3‐dimethyl‐1H‐isoindol‐1‐ones 3 and 3,3‐disubstituted (E)‐1‐(arylimino)‐1,3‐dihydroisobenzofurans 6 has been developed. Thus, treatment of N‐alkyl(or aryl)‐2‐(1‐methylethen‐1‐yl)benzamides 2 with concentrated hydriodic acid (HI) in MeCN at room temperature afforded 3. Similar treatment of N‐aryl‐2‐(1‐phenylethen‐1‐yl)benzamide 5 with concentrated HI