Santana Andrés G, Herrera Antonio J, González Concepción C
Instituto de Productos Naturales y Agrobiología del C.S.I.C., Avenida Astrofísico Francisco Sánchez 3, 38206 La Laguna, Tenerife, Spain.
J Org Chem. 2021 Dec 3;86(23):16736-16752. doi: 10.1021/acs.joc.1c01977. Epub 2021 Nov 22.
Carbamate-bearing benzylated aminosugars undergo an I/I(III)-promoted intramolecular hydrogen atom transfer (IHAT) followed by a nucleophilic attack to provide polycyclic structures. Thus, suitably positioned benzyl ethers are surgically oxidized into the corresponding mixed /-benzylidene acetals, which can be conveniently deprotected under mild acidic conditions to grant access to selectively -deprotected aminosugars amenable for further derivatization. The scope of this strategy has been proven with a series of furanosic and pyranosic scaffolds. Preliminary mechanistic studies, including Hammett LFER and KIE analyses, support a reaction pathway with nucleophilic cyclization as the rate-determining step.
含氨基甲酸酯的苄基化氨基糖在I/I(III)促进下发生分子内氢原子转移（IHAT），随后进行亲核攻击以提供多环结构。因此，适当定位的苄基醚经手术氧化成相应的混合α-亚苄基缩醛，其可在温和酸性条件下方便地脱保护，从而获得适合进一步衍生化的选择性α-脱保护氨基糖。该策略的适用范围已通过一系列呋喃糖和吡喃糖支架得到证明。包括哈米特线性自由能关系（Hammett LFER）和动力学同位素效应（KIE）分析在内的初步机理研究支持以亲核环化作为速率决定步骤的反应途径。
