6 with potassium hydroxide or sodiummethoxide in methanol at room temperature provides 1,2-dihydro[c]benzazepin-3-ones 9. The high product yields and the ease of the reactions under surprisingly mild conditions are particularly intriguing in view of the complex mechanistic pathway involved in the overall transformation. A mechanism based on a multistep rearrangement is proposed, involving conjugated
pyrroloisoquinoline skeleton was established. The reaction sequence involving 6-exo-dig cyclization of alkynyl iminoester and [3+2] cycloaddition of azomethine ylide proceeded smoothly in the presence of 0.5–1.0 mol% (CyJohnPhos)AuCl/AgOTf at 65 or 80 °C. This strategy with (–)-phenylmenthol-derived iminoester enables a generation of chiral azomethine ylide in situ to construct an optically active pyrroloisoquinoline
(HB)‐donor catalysts that bear a 2‐aminoquinazolin‐4‐(1H)‐one or a 3‐aminobenzothiadiazine‐1,1‐dioxide skeleton have been developed, and it has been shown that these catalyst motifs act similarly to other HB‐donor catalysts such as thioureas. The highly enantioselective hydrazination of 1,3‐dicarbonylcompounds was realized even at room temperature with up to 96 % ee for 2‐aminoquinazolin‐4‐(1H)‐one‐type
Dihydro[<i>c</i>]benzazepin-3-ones via Conjugated Nitrone−Allene Precursors
作者:Karin Knobloch、Wolfgang Eberbach
DOI:10.1021/ol0056832
日期:2000.4.1
[formula: see text] Treatment of o-propargylaryl nitrones with base provided 1,2-dihydro[c]benzazepin-3-ones in good yields. The straightforward transformation is explained on the basis of a multistep rearrangement involving conjugated allene-nitrones as precursors of a 1,7-dipolar electrocyclization process that is followed by further bond reorganizations.
Copper-Catalyzed Tandem Cross-Coupling and Alkynylogous Aldol Reaction: Access to Chiral Exocyclic α-Allenols
作者:Guangyang Xu、Zhen Wang、Ying Shao、Jiangtao Sun
DOI:10.1021/acs.orglett.1c01712
日期:2021.7.2
tandem cross-coupling/alkynylogous aldol reaction has been developed. The tetrasubstituted allenoates containing both central and axial chirality have been obtained in moderate to good yields and excellent enantio- and diastereoselectivity. Distinct from the previous use of Cu(I) salts, this protocol features the use of copper(II) salts as a catalytic precursor in this asymmetric cross-coupling reaction
已经开发了对映选择性铜催化串联交叉偶联/炔醇醛醇反应。已经以中等至良好的产率和优异的对映选择性和非对映选择性获得了同时含有中心手性和轴向手性的四取代烯丙酸酯。与之前使用的铜 (I) 盐不同, 该协议的特点是在这种不对称交叉偶联反应中使用铜 (II) 盐作为催化前体。