Photoinduced Palladium-Catalyzed Carbofunctionalization of Conjugated Dienes Proceeding via Radical-Polar Crossover Scenario: 1,2-Aminoalkylation and Beyond
作者:Kelvin Pak Shing Cheung、Daria Kurandina、Tetsuji Yata、Vladimir Gevorgyan
DOI:10.1021/jacs.0c03993
日期:2020.6.3
A photoinduced palladium-catalyzed 1,2-carbofunctionalization of conjugateddienes has been developed. This mild modular approach, which does not require employment of exogeneous photosensitizers and external oxidants, allows for efficient and highly regio- and ste-reoselective synthesis of a broad range of allylic amines from readily available 1,3-dienes, alkyl iodides, and amines. Employment of O-
A Highly Tunable Stereoselective Olefination of Semistabilized Triphenylphosphonium Ylides with <i>N</i>-Sulfonyl Imines
作者:De-Jun Dong、Hai-Hua Li、Shi-Kai Tian
DOI:10.1021/ja910238f
日期:2010.4.14
The Wittigreaction involving direct olefination of triphenylphosphonium ylides (Ph(3)P horizontal lineCHR) with aldehydes is arguably the most often used method for alkene synthesis, but in general it yields mixtures of Z- and E-alkenes for semistabilized triphenylphosphonium ylides (R = aryl or vinyl). We have developed a simple and efficient protocol to improve the stereoselectivity significantly
Boron Lewis Acid-Catalyzed Hydrophosphinylation of <i>N</i>-Heteroaryl-Substituted Alkenes with Secondary Phosphine Oxides
作者:Jimin Han、Jongwon Kim、Jaehoo Lee、Younghun Kim、Sarah Yunmi Lee
DOI:10.1021/acs.joc.0c02246
日期:2020.12.4
secondary phosphine oxides that furnishes various phosphorus-containing N-heterocycles. This process proceeds under mild conditions and enables the introduction of a phosphorus atom into multisubstituted alkenylazaarenes. The available mechanistic data can be explained by a reaction pathway wherein the C–P bond is created by the reaction between the activated alkene (by coordination to a boron catalyst)
Mild and Stereoconvergent Palladium-Catalyzed Carbonyl Alkenation Reaction of α,β-Unsaturated Aldehydes
作者:Manfred Braun、Stefan Mroß、Ido Schwarz
DOI:10.1055/s-1998-1995
日期:1998.1
The addition of preformed ketone and ester enolates to α,β-unsaturated aldehydes 1 followed by in situ protection leads to the carbonates 3, 7, 8, 11, and 13. They are converted into sensitive functionalized dienes 4, 9, 12, and 14 by a smooth palladium-catalyzed elimination. Both syn- and anti-carbonates 7 and 8 lead to E-dienes 9 in a stereoconvergent manner.
Base-tuned selective 1,2-dichloromethylhydroxylation and 1,2-peroxyhydroxylation of 1,3-dienes <i>via</i> a tandem radical process
作者:Jiantao Zhang、Weiming Zhu、Peng Zhou、Cui Chen、Weibing Liu
DOI:10.1039/d3cc02337k
日期:——
catalyst-free 1,2-difunctionalization of 1,3-dienes with CHCl3 and TBHP in the presence of NEt3 to give the dichloromethylhydroxylation products was developed. Various substituents on the aryl ring of the dienes tolerated the reactions and gave the corresponding products in moderate to good yields. When Na2CO3 was employed as the base, the key intermediate α-amino radical could not be formed; therefore
开发了一种在 NEt 3存在下,用 CHCl 3和 TBHP对 1,3-二烯进行无催化剂 1,2-双官能化反应,得到二氯甲基羟基化产物的方法。二烯芳环上的各种取代基可以耐受该反应,并以中等至良好的收率得到相应的产物。当Na 2 CO 3为碱时,不能形成关键中间体α-氨基自由基;因此,得到了1,2-过氧化羟基化产物。该方案为二烯1,2-双官能化提供了一种有效且官能团耐受的策略,从而为合成分子的进一步官能化和修饰提供了巨大的潜力。