A palladium-catalyzed four-component cascade reaction of carbon dioxide, amines, allenyl ethers, and aryl iodides has been developed for the first time. The novel reaction allows simultaneous construction of three different new bonds (C–N, C–O, and C–C) in a single step, affording an efficient method for the synthesis of a variety of highly functionalized acyclic O,O-acetals. Excellent chemo- and regioselectivity
Thermische Umlagerungen von halogensubstituierten Aryl-propargyläthern
作者:Nada Šarčevic̀、Janos Zsindely、Hans Schmid
DOI:10.1002/hlca.19730560502
日期:1973.7.18
7-Chloro-2-chloromethyl-benzofuran (13) and 3, 8-dichloro-2 H-1-benzopyran (12) are the main products from the thermal rearrangement (230–260°) of 2, 6-dichlorophenyl propargyl ether (7). Compounds 17, 18 and 19 are also formed, but in much smaller amounts (scheme 2 and table 1). However, in the case of the bromo-compounds 8 and 9 the rearrangement products are the benzofuran derivatives 21 and 22
7-氯-2-氯甲基苯并呋喃(13)和3,8-二氯2 H -1-苯并吡喃(12)是2,6-二氯苯基炔丙基醚的热重排(230-260°)的主要产物(7)。化合物17,18和19也被形成,但在更小的量(方案2和表1)。然而,在溴化合物8和9的情况下,重排产物是苯并呋喃衍生物21和22,其每分子少含一个溴原子(方案4)。
A Pd−H/Isothiourea Cooperative Catalysis Approach to
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‐Aldol Motifs: Enantioselective α‐Alkylation of Esters with Oxyallenes**
作者:Hua‐Chen Lin、Gary J. Knox、Colin M. Pearson、Chao Yang、Veronica Carta、Thomas N. Snaddon
DOI:10.1002/anie.202201753
日期:2022.6.20
Cooperation between isothiourea and Pd catalysts enables the preparation of anti-aldol products via enantioselective alkylation of esters with oxyallenes. Key to the successful development of this method was the recognition that Pd−H intermediates could be leveraged within this cooperative framework giving access to oxygen-substituted π(allyl)Pd intermediates. Preliminary deuterium-tracking experiments
Photocatalytic Metal Hydride Hydrogen Atom Transfer Mediated Allene Functionalization by Cobalt and Titanium Dual Catalysis
作者:Huaipu Yan、Qian Liao、Yuqing Chen、Gagik G. Gurzadyan、Binghui Lu、Chao Wu、Lei Shi
DOI:10.1002/anie.202302483
日期:2023.6.12
Reported is on the photo Co metal hydride hydrogen atom transfer (MHAT) reaction for chemoselective allene functionalization by using Co-porphines as catalysts and the Hantzsch ester as an H atom and electron donor. The merger of Co MHAT and Ti catalysis under photoredox conditions enabled successful carbonyl allylation, providing access to valuable β-functionalized homoallylic alcohols with exceptional
报道了通过使用 Co-卟啉作为催化剂和 Hantzsch 酯作为 H 原子和电子供体,用于化学选择性丙二烯功能化的照片 Co 金属氢化物氢原子转移 (MHAT) 反应。在光氧化还原条件下,Co MHAT 和 Ti 催化的结合使羰基烯丙基化反应成功,为获得具有特殊区域选择性和非对映选择性的有价值的 β-官能化高烯丙醇提供了途径。
Synthesis of Methylenecyclobutenes by [2+2] Cycloaddition of Allene Ethers and Alkyne
作者:Yi‐Sen Qian
DOI:10.1002/ejoc.202400041
日期:2024.4.2
Methylenecyclobutenes are synthesized via thermal conditions between allene ethers and alkyne and successfully transformed to other four-membered ring compounds. This strategy provides a series of methylenecyclobutenes in moderate yields with broad functional groups.