Six‐ and seven‐membered benzo‐fused cyclic homoallylic alcohols can be readily synthesized by a tandem chiral Brønsted acid‐catalyzed allyl (crotyl)boration/ringclosingmetathesis sequence performed under orthogonal relay catalysis conditions. Excellent enantio‐ and diastereoselectivities are obtained in most of the cases. In addition, the parent crotylboration/RCM process is also described. The required
Enantioselective Synthesis of Polycyclic γ-Lactams with Multiple Chiral Carbon Centers via Ni(0)-Catalyzed Asymmetric Carbonylative Cycloadditions without Stirring
作者:Keita Ashida、Yoichi Hoshimoto、Norimitsu Tohnai、David E. Scott、Masato Ohashi、Hanae Imaizumi、Yuichiro Tsuchiya、Sensuke Ogoshi
DOI:10.1021/jacs.9b12493
日期:2020.1.22
GR-24, a racemic variant of which is a potential seedgermination stimulator and plant-growth regulator. A key of the procedure presented here is a nickel(0)/chiral phosphoramidite-catalyzed asymmetric [2+2+1] carbonylative cycloaddition between readily accessible ene-imines and carbon monoxide, which proceeded enantioselectively to furnish up to 90% ee (>99% ee after recrystallization). The results
Cu-Mediated Sulfonyl Radical-Enabled 5-<i>exo-trig</i> Cyclization of Alkenyl Aldehydes: Access to Sulfonylmethyl 1<i>H</i>-Indenes
作者:Jiabin Ni、Yu Xue、Liping Sun、Ao Zhang
DOI:10.1021/acs.joc.8b00341
日期:2018.4.20
An efficient method for the construction of sulfonylmethyl 1H-indenes via Cu(I)-mediated sulfonyl radical-enabled 5-exo-trigcyclization of alkenyl aldehydes has been developed for the first time. Mechanistic studies indicated that a radical addition–cyclization–elimination (RACE) process might be involved. The reaction features a relatively broad substrate scope, good annulation efficiency, and varying
Synthesis of chroman-4-one and indanone derivatives via silver catalyzed radical ring opening/coupling/cyclization cascade
作者:Qiang Liu、Guanqun Xie、Qiang Wang、Zhendong Mo、Chen Li、Shujiang Ding、Xiaoxia Wang
DOI:10.1016/j.tet.2019.130490
日期:2019.10
conveniently synthesized from readily available cyclopropanols and alkenyl aldehydes via a silver catalyzed radical ring-opening/coupling/cyclization cascade. The reaction proceeded under mild and neutral conditions with broad substrate scope and afforded the desired products in moderate to good yields. A probable mechanism for the cascade reaction was also proposed.
A novel photocatalytic acylarylation of unactivated alkenes using diaryliodonium salts as the arylation reagent is described. The reaction produces a variety of 2-benzyl indanones, 3,4-dihydronaphthalen-1(2H)-ones, and 2,3-dihydroquinolin-4(1H)-ones in promising yields with excellent diastereoselectivity under very mild conditions, which may be appealing for the synthesis of biologically active molecules