chosen as standard C4 units of 1,3-diene precursors. The reactions are believed to undergo a unique cutting and insertion process, involving a CC bond cleavage of the enaminone and insertion of a new C(sp2) source with the formation of two C–C single bonds. A broad range of substrates can be used to synthesize the corresponding 1,3-dienes under very mild reaction conditions, including low catalyst-loading
Enantioselective Hydrothiolation: Diverging Cyclopropenes through Ligand Control
作者:Shaozhen Nie、Alexander Lu、Erin L. Kuker、Vy M. Dong
DOI:10.1021/jacs.1c00939
日期:2021.4.28
In this article, we advance Rh-catalyzed hydrothiolation through the divergent reactivity of cyclopropenes. Cyclopropenes undergo hydrothiolation to provide cyclopropyl sulfides or allylic sulfides. The choice of bisphosphine ligand dictates whether the pathway involves ring-retention or ring-opening. Mechanistic studies reveal the origin for this switchable selectivity. Our results suggest the two
A full account on rhodium‐catalyzed asymmetric, directed hydroboration of functionalized prochiral cyclopropenes affording enantiomerically enriched cyclopropylboronates is reported. The scope and limitations of two alternate directing groups, ester and carboxamide, are evaluated. It was found that hydroboration of esters appeared to be more sensitive to substitution in the aromatic ring of the substrates
Palladium-Catalyzed Living/Controlled Vinyl Addition Polymerization of Cyclopropenes
作者:Zepeng Zhang、Yunpeng Gao、Shufeng Chen、Jianbo Wang
DOI:10.1021/jacs.1c09071
日期:2021.10.27
and ring-opening metathesis polymerization (ROMP), their vinyladditionpolymerization has been sporadically explored, and the corresponding living/controlled polymerization remains a formidable challenge. The major obstacle is the intrinsic instability of the intermediate and the kinetic barrier for propagation. Herein a living/controlled vinyladditionpolymerization of 3-methyl-3-carboxymethyl CPEs
尽管环丙烯 (CPE) 在有机合成和开环复分解聚合 (ROMP) 中具有多种用途,但它们的乙烯基加成聚合已被零星探索,相应的活性/受控聚合仍然是一项艰巨的挑战。主要障碍是中间体的内在不稳定性和传播的动力学障碍。本文展示了由亚磺酰胺双膦配体连接的[Pd(π-allyl)Cl] 2催化的 3-甲基-3-羧甲基 CPE 的活性/受控乙烯基加成聚合。发现在聚合过程中数均分子量 ( M n ) 与转化率的关系图是线性的,分子量分散度 ( M w /M n ) 保持狭窄。Mn值随着单体与催化剂的初始进料比的增加而线性增加。此外,通过顺序单体添加控制嵌段共聚是成功的。所有这些点都证实了这种聚合的活性。催化剂配体和环丙烯部分中的侧羰基的协同配位作用对于以活性/可控方式实现高效聚合起着关键作用。
Rhodium(III)-Catalyzed Enantioselective Benzamidation of Cyclopropenes
作者:Andrey P. Antonchick、Herbert Waldmann、Saad Shaaban、Houhua Li、Christian Merten
DOI:10.1055/s-0040-1706026
日期:2021.7
pharmaceuticals and therefore engaging targets for the development of new methods for their synthesis. Herein the synthesis of enantioenriched cyclopropylamines through catalytic enantioselective C–H functionalization using a chiral RhJasCp complex is reported. The reaction proceeds under mild conditions with high enantiocontrol. This reaction enables access to cyclopropylamines with three contiguous stereocenters
环丙胺是在多种天然产物和药物中发现的特征性结构基序,因此成为开发其合成新方法的目标。本文报道了使用手性Rh Jas Cp配合物通过催化对映选择性CH官能化合成富含对映体的环丙胺。反应在高对映体控制的温和条件下进行。该反应使得能够获得具有源自相应的环丙烯的三个连续的立体中心的环丙胺。