Huang Chia-Yu, Li Jianbin, Li Chao-Jun
Department of Chemistry, FRQNT Center for Green Chemistry and Catalysis, McGill University, Montreal, QC, Canada.
Nat Commun. 2021 Jun 29;12(1):4010. doi: 10.1038/s41467-021-24280-9.
Hydrogen atom abstraction (HAT) from C(sp)-H bonds of naturally abundant alkanes for alkyl radical generation represents a promising yet underexplored strategy in the alkylation reaction designs since involving stoichiometric oxidants, excessive alkane loading, and limited scope are common drawbacks. Here we report a photo-induced and chemical oxidant-free cross-dehydrogenative coupling (CDC) between alkanes and heteroarenes using catalytic chloride and cobalt catalyst. Couplings of strong C(sp)-H bond-containing substrates and complex heteroarenes, have been achieved with satisfactory yields. This dual catalytic platform features the in situ engendered chlorine radical for alkyl radical generation and exploits the cobaloxime catalyst to enable the hydrogen evolution for catalytic turnover. The practical value of this protocol was demonstrated by the gram-scale synthesis of alkylated heteroarene with merely 3 equiv. alkane loading.
从天然丰富的烷烃的C(sp)-H键中提取氢原子（HAT）以生成烷基自由基，这在烷基化反应设计中是一种很有前景但尚未充分探索的策略，因为涉及化学计量的氧化剂、过量的烷烃负载以及适用范围有限是常见的缺点。在此，我们报道了一种使用催化性氯化物和钴催化剂，在烷烃和杂芳烃之间进行的光诱导且无化学氧化剂的交叉脱氢偶联（CDC）反应。含有强C(sp)-H键的底物与复杂杂芳烃之间的偶联反应已以令人满意的产率实现。这个双催化平台的特点是原位产生用于生成烷基自由基的氯自由基，并利用钴肟催化剂实现析氢以进行催化循环。该方法的实用价值通过仅使用3当量烷烃负载量的克级规模合成烷基化杂芳烃得到了证明。
