Kawamoto Takuji, Ryu Ilhyong
Chimia (Aarau). 2012;66(6):372-6. doi: 10.2533/chimia.2012.372.
Tin-free radical hydroxymethylations of haloalkanes using CO and HCHO as a C1 unit proceed efficiently in the presence of borohydrides as radical mediators. In the approach using CO, the formation of aldehydes by radical carbonylation and their subsequent reduction by hydrides lead to alcohols. On the other hand, the use of formaldehyde is more straightforward, in which the key reaction is alkyl radical addition to formaldehyde to give alkoxy radical, which abstracts hydrogen from borohydride reagents. The cascade sequences were observed in the reaction of cholesteryl bromide with HCHO, which displays the diverse applications of HCHO in radical chemistry.
以CO和HCHO作为C1单元，在硼氢化物作为自由基介导剂的存在下，卤代烷烃的无锡自由基羟甲基化反应能高效进行。在使用CO的方法中，通过自由基羰基化形成醛，随后醛被氢化物还原生成醇。另一方面，使用甲醛更为直接，其中关键反应是烷基自由基加成到甲醛上生成烷氧基自由基，烷氧基自由基从硼氢化物试剂中夺取氢。在胆固醇溴化物与HCHO的反应中观察到了串联反应序列，这展示了HCHO在自由基化学中的多种应用。
