Solid-Phase [2+2] Cycloadditions between Chlorosulfonyl Isocyanate and Chiral Vinyl Ethers
作者:Robert Łysek、Bartłomiej Furman、Maciej Cierpucha、Barbara Grzeszczyk、Łukasz Matyjasek、Marek Chmielewski
DOI:10.1002/1099-0690(200207)2002:14<2377::aid-ejoc2377>3.0.co;2-i
日期:2002.7
Vinyl ethers 10, 23, and 33 were attached to Wang resin through the p-oxyphenylsulfonyl linker. The [2+2] cycloadditions between chlorosulfonyl isocyanate and the polymer-bound vinyl ethers 12, 24, and 34, followed by intramolecular alkylation of the β-lactam nitrogen atom, gave mixtures of the corresponding diastereomeric clavams 8/9 and 21/22 or the oxacephams 31/32, accompanied by the oxirane 7
乙烯基醚 10、23 和 33 通过对氧苯基磺酰基接头连接到 Wang 树脂。氯磺酰基异氰酸酯与聚合物结合的乙烯基醚 12、24 和 34 之间的 [2+2] 环加成,然后是 β-内酰胺氮原子的分子内烷基化,得到相应非对映异构体 8/9 和 21/22 的混合物或oxacepham 31/32,分别伴随有环氧乙烷7或氧杂环丁烷30。该环化/裂解步骤是在强有机碱 BEMP 和 DBU 存在下进行的。在溶液中进行的相应反应序列提供了没有伴随的脱水糖的氧杂双环 β-内酰胺。(© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)