Photocatalytic C?C Cleavage of Methylenecyclobutanes for γ,δ-Unsaturated Aldehydes by Strain Release |
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Authors: | Prof?Dr Yan Zhang Chunhang Zhao Chanchan Ma Zhenzhi Cai Sven Trienes Prof?Dr Lutz Ackermann |
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Institution: | 1. Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 321004 Jinhua, China;2. Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany |
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Abstract: | Radical additions onto olefins have surfaced as an increasingly powerful strategy for the synthesis of difunctionalized scaffolds. However, despite of major advances, known approaches continue to be largely limited to two manifolds, namely 1,2-difunctionalization of alkenes and remote difunctionalization via hydrogen atom transfer (HAT). Herein, we describe a mechanistically distinct approach by photoinduced carbon-carbon (C?C) activation/ring-opening to access γ,δ-unsaturated aldehydes from methylenecyclobutanols and sulfonyl chlorides by strain release. Remarkably, the sulfonyl motif on the products was easily removed by another photocatalytic process, which enabled the concise assembly of the natural product alatanone A. The synthetic utility of our approach was reflected by versatile functional group tolerance, ample substrate scope, and scalability. The photocatalysis represents a conceptually distinct alternative to existing approaches for remote 1,4-diversifications, with a double bond remaining in the thus obtained products. |
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Keywords: | Alkene Functionalization Cyclobutanes Photocatalysis Radicals Strain Release |
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