路易斯酸催化炔丙醇和α-二硫缩烯酮[3+2]环加成反应机理研究
详细信息 查看官网全文
- 英文论文题名：Understanding the Mechanism of the Lewis Acid promoted [3+2] cycloadditon of propargylic alcohol and α-Oxo Ketene Dithioacetals
- 论文作者：袁海艳 ; 郑轶莹 ; 张景萍
- 英文论文作者：Haiyan Yuan ; Yiying Zheng ; Jingping Zhang ; Faculty of Chemistry ; Northeast Normal University
- 年：2016
- 作者机构：东北师范大学;
- 论文关键词：BF3·Et2O催化 ; [3+2]环加成 ; 机理 ; 密度泛函理论
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第十九分会：化学中的量子与经典动力学
- 语种：中文
- 分类号：O621.256.7
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第十九分会 ; 化学中的量子与经典动力学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：375k
- 原文格式：D
- 会议级别：全国
摘要
采用密度泛函理论探究BF_3?Et_2O催化炔丙醇和α-二硫缩烯酮的分子间[3+2]环加成反应机理及反应选择性根源。~([1-2])基于底物上羰基氧和醇氧与催化剂间的两种结合模式,我们提出六种合理的反应路径。计算结果表明最优反应机理开始于路易斯酸BF_3对炔丙醇脱羟基、随后得到活性联烯碳阳离子物种来提供活性亲电试剂。整个反应机理经历四个过程:C~α对联烯物中间体上的C1亲核加成、[1,4]-烷硫基迁移、H~α消除、及分子内环化。发现[1,4]-烷硫基迁移过程优于实验上提出的优先环化机理。且底物和催化剂之间的静电和氢键作用在整个反应中起关键作用。
The mechanism and origin of selectivities in BF_3·Et_2O-catalyzed intermolecular [3 + 2] cycloadditions of propargylic alcohol and α-oxo ketene dithioacetals have been studied using density functional theory. Several possible reaction pathways were evaluated on the basis of two possible binding modes between the carbonyl or hydroxyl oxygen of substrates and catalyst. The preferred mechanism initiates dehydroxylation of propargylic alcohol by Lewis acid BF_3 and generates active allenic carbocation species to provide the favorable electrophile. The reaction sequence is in contrast to the mechanism by a previously published study, that is, [1,4]-alkylthio migration occurs prior to the cyclization. Our calculated results suggested that electrostatic attraction and hydrogen-bonding interactions between substrates and catalyst play a vital role in the [3 + 2] cycloaddition.
The mechanism and origin of selectivities in BF_3·Et_2O-catalyzed intermolecular [3 + 2] cycloadditions of propargylic alcohol and α-oxo ketene dithioacetals have been studied using density functional theory. Several possible reaction pathways were evaluated on the basis of two possible binding modes between the carbonyl or hydroxyl oxygen of substrates and catalyst. The preferred mechanism initiates dehydroxylation of propargylic alcohol by Lewis acid BF_3 and generates active allenic carbocation species to provide the favorable electrophile. The reaction sequence is in contrast to the mechanism by a previously published study, that is, [1,4]-alkylthio migration occurs prior to the cyclization. Our calculated results suggested that electrostatic attraction and hydrogen-bonding interactions between substrates and catalyst play a vital role in the [3 + 2] cycloaddition.
引文
[1]Fang,Z.;Liu,J.;Liu,Q.;Bi,X.Angew.Chem.,Int.Ed.2014,53:7209.
[2]Yuan,H.Y.;Zheng,Y.Y.;Zhang,J.P.J.Org.Chem.2016,81:1989.
[2]Yuan,H.Y.;Zheng,Y.Y.;Zhang,J.P.J.Org.Chem.2016,81:1989.