The photolytic and hydrolytic lability of sisyl (Si(SiMe3)3) ethers, an alcohol protecting group
作者:Michael A. Brook、Sonya Balduzzi、Mustafa Mohamed、Christine Gottardo
DOI:10.1016/s0040-4020(99)00562-1
日期:1999.8
The tris(trimethylsilyl)silyl (sisyl) group is a photolabile protecting group for primary and secondary alcohols. Sisyl (tris(trimethylsilyl)silyl) ethers 2b–11b of a number of primary and secondary alcohols 2a–11a were prepared in yields ranging from 70–97%. The resulting silyl ethers were stable to aqueous bases, Grignard reagents and Wittig reagents as would be expected for bulky alkoxysilanes.
三(三甲基甲硅烷基)甲硅烷基(甲硅烷基)是伯醇和仲醇的光不稳定保护基。多种伯醇和仲醇2a-11a中的甲硅烷基(三(三甲基甲硅烷基)甲硅烷基)醚2b-11b制备的产率在70-97%之间。生成的甲硅烷基醚对水性碱,格利雅试剂和维蒂希试剂稳定,这是对大体积烷氧基硅烷所期望的。它们对包括CsF在内的选定氟化物盐也稳定。可以在30分钟内使用254 nm的光解裂解甲硅烷基醚,得到起始醇的产率为62-95%。使用2,3-二甲基-1,3-丁二烯作为甲硅烷基阱,对甲硅烷基醚的光解行为进行了更详细的研究。寡硅烷片段化为亚甲硅的区域化学性质显示取决于烷氧基。三个sisyl醚的水解稳定性与类似比较吨-丁基二甲基甲硅烷基醚。可以通过选择溶剂来改变两个甲硅烷基的相对稳定性:在乙酸/水中,易于水解的顺序为:ROSi(SiMe 3)3 > ROSiMe 2 t -Bu ;使用p -TsOH·H 2 O在CDCl 3中观察到相反的顺序。在AcOH