Substituent Effects and the Mechanism of Gold to Alkene Benzylidene Transfer Employing a Gold Sulfonium Benzylide Complex
Substituent Effects and the Mechanism of Gold to Alkene Benzylidene Transfer Employing a Gold Sulfonium Benzylide Complex
复制标题
金锍苯甲酰配合物金向烯烃苯亚甲基转移的取代效应及机理
DOI：
10.1021/acs.organomet.2c00097
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发表时间：
2022
期刊：
影响因子：
2.8
通讯作者：
Widenhoefer, Ross A.
中科院分区：
文献类型：
--
作者：
Rivers, Mitch;Carden, Robert G.;Widenhoefer, Ross A.
在室温下，脂肪族和芳香族烯烃与金锍苯亚甲基配合物[（P）AuCHPh（SPh 2）]+{B [3，5-CF 3C 6 H3]4}−[P= P（t-Bu）2 o-biphenyl;1]通过阳离子双配位金苯亚甲基配合物[（P）AuCHPh]+（I）快速有效地反应，生成苯环环丙烷。对位取代的乙烯基芳烃对化合物I的反应活性随着乙烯基芳烃给电子能力的降低而降低（ρ = −1.49 ± 0.15），脂肪族烯烃对化合物I的反应活性强烈地依赖于连接在取代程度更高的烯烃末端的烷基数目。亚苄基转移到顺式和反式-β-甲基苯乙烯发生与完全保留的烯烃构型。亚苄基向乙烯基芳烃的转移主要生成顺式环丙烷（dr = 4.1：1 ~ 13.9：1），而亚苄基向脂肪族烯烃的转移选择性较低（dr = 1.3：1 ~ 5.1：1）。我们所有的实验观察是一致的，异步的，亲电苯亚甲基转移机制。的非对映选择性的苄叉转移的过渡态模型的框架内，涉及一个nearanti-periplanar安排的卡宾Au碳和烯烃C碳键的解释。
Aliphatic and aromatic alkenes react rapidly and efficiently with the gold sulfonium benzylide complex [(P)AuCHPh(SPh2)]+{B [3,5-CF3C6H3]4}−[P= P (t-Bu)2o-biphenyl;1] at room temperature via the cationic two-coordinate gold benzylidene complex [(P)AuCHPh]+(I) to form phenyclyclopropanes. The reactivity ofp-substituted vinyl arenes towardIdecreased with the decreasing electron donor ability of the vinyl arene (ρ = −1.49 ± 0.15), and the reactivity of aliphatic alkenes towardIdepended strongly on the number of alkyl groups attached to the more substituted alkene terminus. Benzylidene transfer tocis- andtrans-β-methylstyrene occurred with complete retention of the alkene configuration. Benzylidene transfer to vinyl arenes led to predominant formation ofcis-cyclopropanes (dr = 4.1: 1 to 13.9:1), whereas benzylidene transfer to aliphatic alkenes was generally less selective (dr = 1.3:1 to 5.1:1). All our experimental observations were consistent with a concerted, asynchronous, electrophilic benzylidene transfer mechanism. The diastereoselectivity of benzylidene transfer was interpreted in the framework of a transition state model involving a nearanti-periplanar arrangement of the carbene Au═C and alkene C═C bonds.