Fused bicyclic systems through a ni-mediated intermolecular cyclopentenone annulation
作者:Francisco Camps、Amadeu Llebaria、Josep M. Moretó、Lluís Pagès
DOI:10.1016/s0040-4039(00)77686-6
日期:1992.1
The extension of the Ni(CO)4 promoted carbonylative cycloaddition of acetylenes and allyl halides to the 5–8 membered 3-halocycloolefins leads efficiently to the formation of the corresponding 4–5 fused 2-cyclopentenones with high regio and stereoselectivities.
homoallylic alcohols in good to excellent yields with high diastereoselectivities (>99:1 dr). Reversed diastereoselectivity was obtained when carbonylsubstrate (e. g., 2‐pyridinecarboxaldehyde, glyoxylic acid) containing chelating substituent was used in the allylation reaction. In addition, the reactions involving acyclic (E)‐cinnamyl bromide as substrate worked equally well with high diastereocontrol.
reactions of carbonylcompounds with cyclic allylic halides in the presence of stoichiometric amounts of lithium chloride and a catalytic amount of GaCl3 (20 mol %), leading to the desired homoallylic alcohols in modest to high yields with excellent diastereocontrol (>99:1 syn/anti) and good functional group tolerance. In contrast, the use of either 2-pyridinecarboxaldehyde as the carbonyl substrate or
发现在化学计量的氯化锂和催化量的GaCl 3(20 mol%)存在下,铅有效地介导了羰基化合物与环状烯丙基卤化物的烯丙基化反应,从而以中等收率和高收率得到了所需的均丁醇。出色的非对映控制(> 99:1 syn / anti)和良好的官能团耐受性。相反,使用2-吡啶羧醛作为羰基底物或使用(E)-肉桂基溴化物作为烯丙基化剂产生具有相反的非对映选择性(> 99:1抗/ syn)的相应产物。
Ring-fused and spiro cyclopentenones by Ni(CO)4-promoted intermolecular carbonylative cycloaddition of acetylenes with 3-halo- and 1-(halomethyl)cycloalkenes
作者:Lluis Pages、Amadeu Llebaria、Francisco Camps、Elies Molins、Carles Miravitlles、Josep M. Moreto
DOI:10.1021/ja00052a047
日期:1992.12
The title carbonylativecycloaddition of five- to eight-member ring 3-halo- and 1-(halomethyl)cycloalkenes with different acetylenes was studied. From moderate to good yields of ring-fused and spiro cyclopentenone derivatives were obtained, especially in the reaction with acctylenes bearing electron-withdrawing substituents by propa selection of the reaction conditions to avoid the acetylene polyinsertion
(Guanidine)copper Complex-Catalyzed Enantioselective Dynamic Kinetic Allylic Alkynylation under Biphasic Condition
作者:Xi-Yang Cui、Yicen Ge、Siu Min Tan、Huan Jiang、Davin Tan、Yunpeng Lu、Richmond Lee、Choon-Hong Tan
DOI:10.1021/jacs.7b12806
日期:2018.7.11
Highly enantioselective allylicalkynylation of racemic bromides under biphasic condition is furnished in this report. This approach employs functionalized terminalalkynes as pro-nucleophiles and provides 6- and 7-membered cyclic 1,4-enynes with high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. Enantioretentive derivatizations highlight the synthetic utility of this