“Abnormal” Addition of NHC to a Conjugate Acid of CAAC: Formation of <i>N</i>
-Alkyl-Substituted CAAC
作者:Debdeep Mandal、Ramapada Dolai、Pankaj Kalita、Ramakirushnan Suriya Narayanan、Ravi Kumar、Sebastian Sobottka、Biprajit Sarkar、Gopalan Rajaraman、Vadapalli Chandrasekhar、Anukul Jana
DOI:10.1002/chem.201802587
日期:2018.8.27
The addition reactions of N‐heterocyclic carbenes (NHCs) are mostly known to occur through the carbenic centre (C2), which leads to a “normal” adduct. Herein, we report the “abnormal” addition of NHCDip 1 (1,3‐(2,6‐iPr2C6H3)‐imidazole‐2‐ylidene) to a conjugate acid of cyclic (alkyl)(amino)carbene 2 (CAACiPr=1‐iPr‐3,3,5,5‐Me4‐pyrrolinium triflate). Mechanistic study revealed that this reaction proceeded
N-杂环卡宾(NHC)的加成反应通常是通过卡宾中心(C2)发生的,这导致“正常”加合物。在此,我们报告了NHC Dip 1(1,3-(2,6 - i Pr 2 C 6 H 3)-咪唑-2-亚烷基)“异常”添加到环状(烷基)(氨基)共轭酸中的情况。卡宾2(CAAC i Pr = 1‐ i Pr‐3、3、5、5‐Me 4‐吡咯啉三氟甲磺酸盐)。机理研究表明,该反应通过原位形成1,3-(2,6 - i Pr 2 C 6 H 3)-咪唑阳离子进行4和Ni个镨取代CAAC 5随后氧化加成化合物5化合物的跨C4-H键(别名骨干C-H)4。化合物5的原位形成还通过将其氧化添加到i PrNH 2的NH基团中来证明。DFT计算也支持了机理发现。还描述了通过使用TMPLi原位产生化合物5的另一种方法。