State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry and the University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China.
J Org Chem. 2020 Nov 6;85(21):14121-14138. doi: 10.1021/acs.joc.0c02180. Epub 2020 Oct 27.
It is long known that dihydroperoxidation of aliphatic aldehydes is extremely difficult and normally stops halfway at the hydroxyhydroperoxide stage. This strange phenomenon now has been explored, and a highly effective protocol for conversion of aliphatic aldehydes into -dihydroperoxides has been developed. Silyl protection of primary -dihydroperoxides, which is also a challenge due to unexpected based-induced decomposition, was achieved using 2,6-lutidine as the base. The silyl-protected -dihydroperoxides were then examined in a peroxycarbenium [3 + 2] cycloaddition reaction with alkenes for the first time. Aromatic substrates normally reacted smoothly, affording the expected 1,2-dioxolanes smoothly. Aliphatic aldehydes generally failed to yield 1,2-dioxolane. In all cases, unexpected formation of either a chlorohydrin or a 1,2-dichloride (with Cl atoms derived from TiCl) depending on the alkene employed was observed, which displays some so far unknown facets of the cycloaddition and helped to gain many mechanistic insights.
长期以来，人们都知道脂肪醛的二氢过氧化物化非常困难，通常在羟基过氧化物阶段就会中途停止。现在，这种奇怪的现象已经被探索出来，并且已经开发出一种将脂肪醛转化为β-二氢过氧化物的高效方法。由于基诱导的分解而导致的难以预料的情况，使用 2,6- 二甲基吡啶作为碱来实现伯β-二氢过氧化物的硅保护。然后，首次在过氧碳正离子[3+2]环加成反应中用硅保护的β-二氢过氧化物与烯烃进行了研究。芳香族底物通常反应顺利，顺利地得到了预期的 1,2-二氧杂环戊烷。而脂肪醛通常不能生成 1,2-二氧杂环戊烷。在所有情况下，根据所使用的烯烃，观察到了要么形成氯醇，要么形成 1,2-二氯化物（其中的 Cl 原子来自 TiCl），这显示了环加成反应的一些迄今未知的方面，并有助于获得许多机制见解。
