Hypervalent (<i>tert</i>-Butylperoxy)iodanes Generate Iodine-Centered Radicals at Room Temperature in Solution: Oxidation and Deprotection of Benzyl and Allyl Ethers, and Evidence for Generation of α-Oxy Carbon Radicals
作者:Masahito Ochiai、Takao Ito、Hideo Takahashi、Akinobu Nakanishi、Mika Toyonari、Takuya Sueda、Satoru Goto、Motoo Shiro
DOI:10.1021/ja9610287
日期:1996.1.1
reductive deprotection. Oxidation with 1a occurs readily with C−H bonds activated by both enthalpic effects (benzylic, allylic, and propargylic C−H bonds) and/or polar effects (α-oxy C−H bonds), generating α-oxy carbon-centered radicals, which can be detected by nitroxyl radical trapping. Measurement of the relative rates of oxidation for a series of ring-substituted benzyl n-butyl ethers 2d and 2p−s
1-(tert-Butylperoxy)-1,2-benziodoxol-3(1H)-one (1a) 在室温下,在苯或环己烷中,在碱金属碳酸盐存在下,将苄基和烯丙基醚氧化成酯。由于该反应与其他保护基团(例如 MOM、THP 和 TBDMS 醚以及乙酰氧基)相容,并且由于酯在碱性条件下容易水解,因此这种新方法为通常的还原性脱保护提供了一种方便有效的替代方法。与 1a 的氧化很容易发生,C-H 键被焓效应(苄基、烯丙基和炔丙基 C-H 键)和/或极性效应(α-氧 C-H 键)激活,生成 α-氧碳中心自由基,可以通过硝酰基自由基捕获来检测。