Catalytic, enantioselective, intramolecular carbosulfenylation of olefins. Mechanistic aspects: a remarkable case of negative catalysis.
Catalytic, enantioselective, intramolecular carbosulfenylation of olefins. Mechanistic aspects: a remarkable case of negative catalysis.
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DOI：
10.1021/ja413270h
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发表时间：
2014-03-05
影响因子：
15
通讯作者：
Chi HM
中科院分区：
文献类型：
--
作者：
Denmark SE;Chi HM
在开发对映选择性的刘易斯碱/布朗斯特酸共催化烯烃的碳硫基化的过程中，出现了一个看似不可能的难题：催化剂如何抑制化学计量反应？尽管观察到非常好的对映选择性，但未催化反应的速率（即，无刘易斯碱）与催化方法相当或稍快。详细的动力学和光谱研究的组合揭示了答案不是刘易斯碱催化剂的直接参与，而是其转化为催化活性亚磺酰化剂的次要后果。手性亚磺酰化物质的产生伴随着形成等摩尔量的磺酸根离子和邻苯二甲酰亚胺，其用于缓冲剩余的布朗斯台德酸，从而抑制外消旋背景反应。因此，通过简单地除去催化剂不能很好地模拟在催化条件下操作的实际背景反应。
In the course of developing an enantioselective, Lewis base/Brønsted acid co-catalyzed carbosulfenylation of alkenes, a seemingly impossible conundrum arose: How could a catalyst inhibit a stoichiometric reaction? Despite the observation of very good enantioselectivities, the rate of the uncatalyzed reaction (i.e., no Lewis base) was found to be comparable to or slightly faster than that of the catalyzed process. A combination of detailed kinetic and spectroscopic studies revealed that the answer is not the direct involvement of the Lewis base catalyst, but rather the secondary consequences of its conversion to the catalytically active sulfenylating agent. Generation of the chiral sulfenylating species is accompanied by the formation of equimolar amounts of sulfonate ion and phthalimide which serve to buffer the remaining Brønsted acid and thus inhibit the racemic background reaction. Thus, the actual background reaction operative under catalytic conditions is not well mimicked by simply removing the catalyst.
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影响因子：
5.2
作者：
Denmark, Scott E.;Collins, William R.
通讯作者：
Collins, William R.
影响因子：
1.6
作者：
Hojo, M;Chen, ZD
通讯作者：
Chen, ZD
影响因子：
15
作者：
Denmark, Scott E.;Kornfilt, David J. P.;Vogler, Thomas
通讯作者：
Vogler, Thomas
影响因子：
15
作者：
Denmark, Scott E.;Jaunet, Alex
通讯作者：
Jaunet, Alex
DOI：
10.1126/science.1182826
发表时间：
2010-02-19
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Xu H;Zuend SJ;Woll MG;Tao Y;Jacobsen EN
通讯作者：
Jacobsen EN