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Nickel-Catalyzed C–C Activation of Vinylcyclobutane with Visible Light: Scope, Mechanism, and Application to Chemically Recyclable Polyolefins
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2024-08-30 , DOI: 10.1021/jacs.4c04611 Cherish Nie 1 , Chloe Park 1 , Junho Kim 1 , Paul J Chirik 1
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2024-08-30 , DOI: 10.1021/jacs.4c04611 Cherish Nie 1 , Chloe Park 1 , Junho Kim 1 , Paul J Chirik 1
Affiliation
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N-heterocyclic carbene (NHC)-supported nickel complexes were investigated for the oxidative ring-opening of vinylcyclobutane (VCB) and photocatalytic activity. Addition of VCB to in situ generated [(NHC)Ni(0)] compounds furnished (NHC)Ni(VCB)2 that underwent oxidative addition and conversion to the corresponding Ni(II) alkyl, allyl-metallacycles. The (NHC)Ni(C6H10) metallacycles were isolated, characterized, and exhibited high thermal and chemical stability. Irradiation with visible light at ambient temperature produced a mixture of ethylene and 4-vinylcyclohexene and 1,5-cyclooctadiene, cycloaddition dimers of butadiene, arising from formal retro-[2 + 2] cycloaddition. A mixture of hexadiene products arising from β-H elimination from the metallacycle was also observed. Free ethylene also underwent a secondary reaction to form cyclopropane products through formal [2 + 1] cycloaddition. A series of sterically and electronically modified NHC ligands was evaluated to establish the structure–activity relationship governing the rate of photocatalytic conversion of VCB and the resulting product distribution. Isotopic labeling experiments, resting state analysis, and independent synthesis of a range of nickel bis(olefin) complexes provided insight into the mechanism of the reaction and origins of the organic product mixture. (NHC)Ni-catalysis was also applied toward the retro-[2 + 2] depolymerization of (1,n′-divinyl)-oligocyclobutane to butadiene dimers.
中文翻译：
可见光下镍催化的乙烯基环丁烷 C-C 活化：范围、机理以及在化学可回收聚烯烃中的应用
研究了 N-杂环卡宾 (NHC) 负载的镍配合物对乙烯基环丁烷 (VCB) 的氧化开环和光催化活性。将 VCB 添加到原位生成的 [(NHC)Ni(0)] 化合物中，得到 (NHC)Ni(VCB) 2 ，该化合物经历氧化加成并转化为相应的 Ni(II) 烷基、烯丙基金属环。 (NHC)Ni(C 6 H 10 )金属环被分离、表征，并表现出较高的热稳定性和化学稳定性。在环境温度下用可见光照射产生乙烯和4-乙烯基环己烯和1,5-环辛二烯的混合物，丁二烯的环加成二聚体，由正式的逆-[2+2]环加成产生。还观察到由金属环中的β-H消除产生的己二烯产物的混合物。游离乙烯还经历了二次反应，通过正式的[2+1]环加成形成环丙烷产物。对一系列空间和电子修饰的 NHC 配体进行了评估，以建立控制 VCB 光催化转化率和所得产物分布的结构-活性关系。同位素标记实验、静息态分析和一系列镍双（烯烃）络合物的独立合成提供了对反应机制和有机产物混合物来源的深入了解。 (NHC)Ni 催化还应用于 (1, n'-二乙烯基)-低聚环丁烷的逆[2 + 2]解聚为丁二烯二聚体。
更新日期：2024-08-30
中文翻译：
可见光下镍催化的乙烯基环丁烷 C-C 活化：范围、机理以及在化学可回收聚烯烃中的应用
研究了 N-杂环卡宾 (NHC) 负载的镍配合物对乙烯基环丁烷 (VCB) 的氧化开环和光催化活性。将 VCB 添加到原位生成的 [(NHC)Ni(0)] 化合物中，得到 (NHC)Ni(VCB) 2 ，该化合物经历氧化加成并转化为相应的 Ni(II) 烷基、烯丙基金属环。 (NHC)Ni(C 6 H 10 )金属环被分离、表征，并表现出较高的热稳定性和化学稳定性。在环境温度下用可见光照射产生乙烯和4-乙烯基环己烯和1,5-环辛二烯的混合物，丁二烯的环加成二聚体，由正式的逆-[2+2]环加成产生。还观察到由金属环中的β-H消除产生的己二烯产物的混合物。游离乙烯还经历了二次反应，通过正式的[2+1]环加成形成环丙烷产物。对一系列空间和电子修饰的 NHC 配体进行了评估，以建立控制 VCB 光催化转化率和所得产物分布的结构-活性关系。同位素标记实验、静息态分析和一系列镍双（烯烃）络合物的独立合成提供了对反应机制和有机产物混合物来源的深入了解。 (NHC)Ni 催化还应用于 (1, n'-二乙烯基)-低聚环丁烷的逆[2 + 2]解聚为丁二烯二聚体。
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