在伯和仲甲硅烷基醚和芳基醚的存在下,由B(C 6 F 5)3 / Et 3 SiH促进的催化C(sp 3)-O键裂解优先与伯甲苯磺酸盐一起进行。这种反应性的差异使几种1,n-二醇的化学选择性脱官能化,并且正交保护的碳水化合物的羟甲基选择性脱氧突出了新方法的效率。具有邻苯基的甲苯磺酸酯在邻氨基苯甲酸辅助下被裂解。
The chemoselective and efficient deprotection of silyl ethers using trimethylsilyl bromide
作者:Syed Tasadaque A. Shah、Patrick J. Guiry
DOI:10.1039/b803949f
日期:——
An efficient and chemoselective cleavage of silyl ethers (primary, secondary and aromatic) by using catalytic quantities of trimethylsilylbromide (TMSBr) in methanol is reported. A wide range of alkyl silyl ethers such as TBS, TIPS, and TBDPS can be chemoselectively cleaved in high yield in the presence of aryl silyl ethers. The deprotection of silyl esters was also achieved employing catalytic quantities
An iron(III) salt catalyzed retro-Claisencondensation between an alcohol and a 1,3-diketone was investigated. The mechanism involves the formation of a metal-induced six-membered cyclic transition state and cleavage of the C–C bond. Regioselective esterification and one-pot conversion of silyl ethers into esters with good yields was observed. Simple reaction conditions, high yields, and broad scope
permits selective deprotection of aliphatic TBS ethers in good to excellent yields in the presence of aromatic TBS ethers, aliphatic triisopropylsilyl ethers, aliphatic tert-butyl(diphenyl)silylethers, or sterically hindered aliphatic TBS ethers. Additionally, TBS ethers can also be transformed into 4-methoxybenzyl ethers or methyl ethers in one pot by using larger quantities of the catalyst and a higher
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 protectinggroup 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.
Mild and Highly Selective Formyl Protection of Primary Hydroxyl Groups
作者:Lidia De Luca、Giampaolo Giacomelli、Andrea Porcheddu
DOI:10.1021/jo0257492
日期:2002.7.1
Efficient conversion of primary alcohols to the corresponding formate esters can be carried out at room temperature in methylene chloride, using 2,4,6-trichloro-1,3,5-triazine and N,N-dimethylformamide in the presence of lithium fluoride. This procedure appears as a valid method for selectively protecting primaryhydroxylgroups.