Cobalt-Catalyzed Enantio- and Diastereoselective Intramolecular Hydroacylation of Trisubstituted Alkenes
作者:Junfeng Yang、Alice Rérat、Yang Jie Lim、Corinne Gosmini、Naohiko Yoshikai
DOI:10.1002/anie.201611518
日期:2017.2.20
Enantio‐ and diastereoselectivesynthesis of trans‐2,3‐disubstituted indanones is achieved by intramolecular hydroacylation of 2‐alkenylbenzaldehydes bearing trisubstituted alkenyl groups under cobalt‐chiral diphosphinecatalysis. Notably, a high level of enantioselectivity is induced regardless of the stereochemistry (E/Z ratio) of the alkenyl group of the starting material. Deuterium‐labeling experiments
reductive cyclization of easily accessible benz-tethered 1,3-dienes containing a ketone moiety. This process provided biologically active 1,2-dihydronaphthalene-1-ol derivatives in good yields with excellent enantio- and diastereoselectivity. Mechanistic investigations using density functional theory revealed that (Z)- and (E)-allylcopper intermediates formed in situ from the diene and copper catalyst
Photoredox/Nickel Dual Catalysis-Enabled Modular Synthesis of Arylallyl Alcohols with Acetylene as the Two-Carbon Synthon
作者:Kangkui Li、Xianyang Long、Shifa Zhu
DOI:10.1021/acscatal.2c06178
日期:2023.2.17
alcohols were synthesized in an acetylene atmosphere (1 atm). This method features broad substrate scopes, good functional group tolerance, and high Z-selectivity. In addition to the intermolecular difunctionalization of acetylene, the reaction is also amenable to intramolecular ring formation, giving highly valuable indenols and indanones. The mechanistic investigation indicates that the alkenylnickel
Synthesis of Dibenzo[<i>b</i>,<i>f</i>]azepines via Palladium‐Catalyzed Cascade [4 + 3] Annulation of <i>o</i>‐Alkenyl Bromoarenes and <i>o</i>‐Bromoaniline Derivatives
A cascade [4+3] annulation of o-alkenyl bromoarenes and o-bromoaniline derivatives was described. Various dibenzo[b,f]azepines with substitutions on the 10/11 position were obtained in 14–97% yields. The synthetic versatility of this protocol is highlighted by the preparation of a precursor of the drug molecule oxcarbazepine, a gram-scale synthesis, and two product transformations. Unlike previous
描述了邻-烯基溴芳烃和邻-溴苯胺衍生物的级联[ 4+3]环化。获得了在 10/11 位点上有取代的各种二苯并[ b , f ]氮杂卓化合物,产率为 14-97%。该方案的合成多功能性通过药物分子奥卡西平前体的制备、克级合成和两种产品转化来突出。与之前的胺化/Heck 序列不同,该级联过程应该经历 C(乙烯基)、C(芳基)-钯环参与途径。
Photoinduced C−Br Homolysis of 2-Bromobenzophenones and Pschorr Ring Closure of 2-Aroylaryl Radicals to Fluorenones
作者:Jarugu Narasimha Moorthy、Subhas Samanta
DOI:10.1021/jo7017872
日期:2007.12.1
[Graphics]A variety of diversely substituted 2-aroylaryl radicals, generated by photoinduced homolysis of 2-bromoarylketones, is shown to undergo Pschorr cyclization to yield fluorenones in moderate to excellent yields. The photochemical results illustrate that the substituents in the two phenyl rings of the 2-bromobenzophenone skeleton exert a dramatic influence on the reactivity of the derived 2-aroylaryl radicals. The disubstitution by methoxy groups in the radical ring renders the aryl sigma-radical highly electrophilic and unreactive for hydrogen abstraction and cyclization. On the other hand, the substituents in the non-radical ring that strongly stabilize the hydrofluorenyl pi-radical, formed subsequent to the attack of the 2-aroylaryl radical on the non-radical ring, promote cyclization to furnish fluorenones in excellent isolated yields.