Dearomatizing Radical Cyclizations and Cyclization Cascades Triggered by Electron-Transfer Reduction of Amide-Type Carbonyls

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• 作者：Huan-Ming HuangDavid J. Procter
• 刊名：Journal of the American Chemical Society
• 出版年：2017
• 出版时间：February 1, 2017
• 年：2017
• 卷：139
• 期：4
• 页码：1661-1667
• 全文大小：814K
• ISSN：1520-5126

文摘

Highly selective dearomatizing radical cyclizations and cyclization cascades, triggered by single electron transfer to amide-type carbonyls by SmI<sub>2sub>–H<sub>2sub>O–LiBr, provide efficient access to unprecedented spirocyclic scaffolds containing up to five stereocenters with high diastereocontrol. The first dearomatizing radical cyclizations involving radicals derived from amide carbonyls by single electron transfer take place under mild conditions and engage a range of aromatic and heteroaromatic systems present in the barbiturate substrates. The radical cyclizations deliver new polycyclic hemiaminals or enamines selectively, depending on the conditions employed, that are based on a medicinally proven scaffold and can be readily manipulated.