Cobalt Nanoparticles-Catalyzed Widely Applicable Successive C-C Bond Cleavage in Alcohols to Access Esters

Selective cleavage and functionalization of C-C bonds have important applications in organic synthesis and biomass utilization. However, functionalization of C-C bonds by controlled cleavage remains difficult and challenging because they are inert. Herein, we describe an unprecedented efficient protocol for the breaking of successive C-C bonds in alcohols to form esters with one or multiple carbon atoms less using heterogeneous cobalt nanoparticles as catalyst with dioxygen as the oxidant. A wide range of alcohols including inactive long-chain alkyl aryl alcohols undergo smoothly successive cleavage of adjacent -(C-C)(n)- bonds to afford the corresponding esters. The catalyst was used for seven times without any decrease in activity. Characterization and control experiments disclose that cobalt nanoparticles are responsible for the successive cleavage of C-C bonds to achieve excellent catalytic activity, while the presence of Co-N(x)has just the opposite effect. Preliminary mechanistic studies reveal that a tandem sequence reaction is involved in this process.

碳 - 碳键的选择性裂解和官能化在有机合成和生物质利用中具有重要应用。然而，由于碳 - 碳键具有惰性，通过可控裂解对其进行官能化仍然困难且具有挑战性。在此，我们描述了一种前所未有的高效方案，即使用多相钴纳米粒子作为催化剂，以氧气作为氧化剂，使醇中的连续碳 - 碳键断裂形成少一个或多个碳原子的酯。包括不活泼的长链烷基芳基醇在内的多种醇都能顺利地使相邻的 - (C - C)(n)- 键连续断裂，生成相应的酯。该催化剂使用了7次，活性没有任何降低。表征和对照实验表明，钴纳米粒子负责碳 - 碳键的连续断裂以实现优异的催化活性，而Co - N(x)的存在则起到相反的作用。初步的机理研究表明，该过程涉及一个串联顺序反应。