氮杂环丙烯鎓盐和硫叶立德的[3 + 1]-和[3 + 2]-环加成反应。
[3 + 1]- and [3 + 2]-Cycloadditions of Azaoxyallyl Cations and Sulfur Ylides.
机构信息
College of Pharmacy, Third Military Medical University , Shapingba, Chongqing 400038, China.
Key Laboratory of Drug-Targeting and Drug Delivery System of the Ministry of Education, West China School of Pharmacy, Sichuan University , Chengdu 610041, China.
出版信息
Org Lett. 2016 Jun 3;18(11):2738-41. doi: 10.1021/acs.orglett.6b01194. Epub 2016 May 20.
A new formal [3 + 1]-cycloaddition reaction of azaoxyallyl cation intermediates, generated in situ from α-halo hydroxamates bearing α-alkyl groups, and sulfur ylides is reported, furnishing useful β-lactams (dr >19:1) in fair to modest yields. In contrast, an unexpected formal [3 + 2]-cycloaddition reaction occurs to give γ-lactam derivatives for α-halo hydroxamates with α-aryl groups and sulfur ylides in the presence of bases.
报告了一种新的[3+1]环加成反应，涉及氮杂氧烯正离子中间体的生成，该中间体由带有α-烷基的α-卤代羟胺酸原位生成，并与硫叶立德反应，生成有用的β-内酰胺（dr＞19：1），产率适中至尚可。相比之下，在碱的存在下，α-卤代羟胺酸与α-芳基和硫叶立德反应时，会发生意想不到的[3+2]环加成反应，生成γ-内酰胺衍生物。
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