Investigations of α-siloxy-epoxide ring expansions forming 1-azaspirocyclic ketones

被引：34

作者：

Dake, GR ^{[1
]}

Fenster, MDB ^{[1
]}

Fleury, M ^{[1
]}

Patrick, BO ^{[1
]}

机构：

[1] Univ British Columbia, Dept Chem, Vancouver, BC V6T 1Z1, Canada

来源：

JOURNAL OF ORGANIC CHEMISTRY | 2004年 / 69卷 / 17期

关键词：

D O I：

10.1021/jo049356+

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The construction of 1-azaspirocyclic cycloalkanones using a siloxy-epoxide semipinacol ring expansion process was examined. Functionalized 1-azaspiro[5.5]undecan-7-ones (1-azaspirocyclic cyclohexanones) proceeded in high chemical yields with complete diastereoselectivity using titanium tetrachloride as the Lewis acid promoter. The formation of functionalized 6-azaspiro[5.4]-decan-1-ones (1-azaspirocyclic cyclopentanones) proceeded in high chemical yield with little diastereoselectivity. Modification of reaction parameters such as the Lewis acid promoter or the nature of the silyl ether allowed for the preferential formation of either ("anti" or "syn" 1,2 alkyl shift) diastereomeric product. An explanation for the different reactivity profiles between the cyclobutanol silyl ethers and cyclopentanol silyl ethers is provided.

引用

页码：5676 / 5683

页数：8

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