An Efficient Stereoselective Synthesis of 4,5-trans-1,5-cis-3-Oxabicyclo[3.1.0]hexan-2-ones via the Iodolactonization of Alkylidenecyclopropyl Esters
摘要:
A highly stereoselective iodolactonization of alkylidenecyclopropyl esters with iodine or N-iodosuccinimide (NIS) in aqueous CH3CN to afford 4,5-trans-1,5-cis-3-oxabicyclo-[3.1.0]hexane-2ones is described. The reaction is very general, accommodating a wide range of substituents. A plausible mechanism that explains the essential role of water in this reaction is proposed.
Palladium Acetate-Catalyzed Cyclization Reaction of 2,3-Allenoic Acids in the Presence of Simple Allenes: An Efficient Synthesis of 4-(1‘-Bromoalk-2‘(<i>Z</i>)-en-2‘-yl)furan-2(5<i>H</i>)-one Derivatives and the Synthetic Application
作者:Zhenhua Gu、Xinke Wang、Wei Shu、Shengming Ma
DOI:10.1021/ja072790j
日期:2007.9.1
We have realized a cyclizationreaction of 2,3-allenoicacids 1 in the presence of simple alkyl- or aryl-substituted allenes 3. In this reaction, the cyclic oxypalladation of 2,3-allenoicacid with Pd(II) would afford the furanonyl palladium intermediate 2, which could be trapped by the simple allene to afford a pi-allylic intermediate anti-9. This intermediate anti-9 could be nucleophilically attacked
Synthesis and transformations of metallacycles 41. Cyclomagnesiation of O-containing 1,2-dienes with Grignard reagents in the presence of Cp2TiCl2
作者:V. A. D’yakonov、A. A. Makarov、E. Kh. Makarova、L. M. Khalilov、U. M. Dzhemilev
DOI:10.1007/s11172-012-0269-1
日期:2012.10
A Cp2TiCl2-catalyzed intermolecular homocyclomagnesiation of O-containing 1,2-dienes and cross-cyclomagnesiation of O-containing 1,2-dienes with aliphatic 1,2-dienes of cyclic and acyclic structure have been accomplished using Grignard reagents, which led to mono- and bicyclic organomagnesium compounds in 61–94% yields.
Development of a New Spiro-BOX Ligand and Its Application in Highly Enantioselective Palladium-Catalyzed Cyclization of 2-Iodoanilines with Allenes
作者:Wei Shu、Qiong Yu、Shengming Ma
DOI:10.1002/adsc.200900607
日期:2009.11
In this communication, we report the synthesis of a new chiral spiro-bisoxazoline ligand, i.e., β-naphthylmethyl-substituted spiro-BOX [(Ra,S,S)-L7] and have successfully applied it to the palladium-catalyzedenantioselectivecyclization reaction of simple allenes with o-aminoiodobenzenes, affording highly optically active 3-alkylideneindolines in good yields with excellent enantiomeric excesses.
An Efficient Approach to 2-Bromoalken-3-ols by Regioselective Bromohydroxylation Reaction of Simple Allenes with NBS
作者:Wangqing Kong、Binjie Guo、Chunling Fu、Shengming Ma
DOI:10.1002/ejoc.201001676
日期:2011.4
A regioselectivebromohydroxylationreaction of simpleallenes affording 2-bromoalken-3-ols in moderate-to-good yields has been developed by using NBS as the electrophilic reagent in a mixture of 1,4-dioxane/H 2 O (1:1) at room temperature. Through this study it has been concluded that the regioselectivity is determined by various factors including steric and electronic effects of the substituents
通过在 1,4-二恶烷/H 2 O (1:1) 混合物中使用 NBS 作为亲电试剂,开发了简单丙二烯的区域选择性溴羟基化反应,以中等至良好的收率提供 2-bromoalken-3-ols在室温下。通过这项研究得出的结论是,区域选择性由各种因素决定,包括丙二烯部分取代基的空间和电子效应。
Synthese de dienes-1,3 et de styrenes fonctionnalises par carbopalladation catalytique d'allenes
作者:Mohammed Ahmar、Bernard Cazes、Jacques Gore
DOI:10.1016/s0040-4039(01)81478-7
日期:1984.1
The palladium (O) catalyzed reaction of aryl and vinyl halides with allenes in the presence of sodium ethyl malonate leads with good yields and in certain cases with high stereoselectivity to styrenes and 1,3-butadienes derivatives.