Catalytic Multisite-Selective Acetoxylation Reactions at sp<sup>2</sup> vs sp<sup>3</sup> C–H Bonds in Cyclic Olefins
作者:Zhong-Lin Zang、Sheng Zhao、Shuklachary Karnakanti、Cheng-Lin Liu、Pan-Lin Shao、Yun He
DOI:10.1021/acs.orglett.6b02458
日期:2016.10.7
The first Pd-catalyzed multisite-selective acetoxylation reactions are disclosed at an unactivated alkene sp2 C–H bond versus secondary allylic sp3 C–H bond in cyclic olefins via the modulation of directing groups. The different directing groups overcome the key challenge in differentiating C–H bonds and provide a new controlling approach for site-specific C–H activation. A wide variety of substrates
Diastereoselective Synthesis of Polysubstituted Piperidines through Visible‐Light‐Driven Silylative Cyclization of Aza‐1,6‐Dienes: Experimental and DFT Studies
作者:Wei‐Chen Cui、Wenxuan Zhao、Ming Gao、Wei Liu、Shaozhong Wang、Yong Liang、Zhu‐Jun Yao
DOI:10.1002/chem.201903440
日期:2019.12.20
and an electron-neutral olefin was developed, which allows for stereoselective synthesis of densely functionalized piperidines in a highly atom-economical manner. Depending on the substitution pattern of the electron-neutral olefin, poor-to-excellent diastereoselectivity was observed. It was suggested that the 6-exo-trig cyclization was initiated by a chemoselective addition of silyl radical toward
Cationic Divalent Metal Sites (M = Mn, Fe, Co) Operating as Both Nitrene-Transfer Agents and Lewis Acids toward Mediating the Synthesis of Three- and Five-Membered<i>N</i>-Heterocycles
practicable yields, involving a single-pot cycloaddition reaction of alkene, nitrene, and ketone (2 + 1 + 2). Mechanistic studies indicate that the most productive bipodal Fe(II) site mediates stepwise addition of nitrene to olefins to generateaziridines with good retention of stereochemistry and further enables aziridine ring opening to unmask a 1,3-zwitterion that can undergo cycloaddition with dipolarophiles
Domino Aryne Annulation via a Nucleophilic–Ene Process
作者:Hai Xu、Jia He、Jiarong Shi、Liang Tan、Dachuan Qiu、Xiaohua Luo、Yang Li
DOI:10.1021/jacs.8b01005
日期:2018.3.14
1,2-Benzdiyne equivalents possess the unique property that they can react with two arynophiles through iteratively generated 1,2- and 2,3-aryne intermediates. Upon rational modification on the second leaving group of these aryne precursors, a domino aryne annulation approach was developed through a nucleophilic-ene reaction sequence. Various benzo-fused N-heterocyclic frameworks were achievable under transition metal-free conditions with a broad substrate scope.
Palladium-Catalyzed Rearrangement of Allylic Sulfoximines: Application to the Asymmetric Synthesis of Chiral Allylic Amines
作者:Stephen G. Pyne、Zemin Dong
DOI:10.1021/jo9605105
日期:1996.1.1
The palladium(0)-catalyzed reactions of the primary and secondary allylic sulfoximines 7, 9, 11, 13, 15, 17, and 19 gives allylic sulfinamides without 1,3-allylic rearrangement. These compounds were not isolated but were converted to their corresponding N-tosyl allylic amines, primary and secondary 8, 10, 12, 14, 16, 18, and 20, respectively. In the case of the optically active secondary allylic sulfoximines 17 and 19, chiral N-tosyl allylic secondary amines were formed in high enantiomeric purities.