Copper‐Catalyzed Aerobic CC Bond Cleavage of Lactols with N‐Hydroxy Phthalimide for Synthesis of Lactones. Issue 4 (13th November 2014)

• Record Type: Journal Article
• Authors: Tnay, Ya Lin; Chiba, Shunsuke
• Is Part Of: Chemistry, an Asian journal. Volume 10:Issue 4(2015:Apr.)
• Page Start: 873
• Page End: 877
• Publication Date: 2014-11-13
• Subjects: CC bond cleavage -- copper -- homogeneous catalysis -- lactones -- radicals; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201403196
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: The transformation of cyclic hemiacetals (lactols) into lactones has been achieved by Cu‐catalyzed aerobic CC bond cleavage in the presence of N ‐hydroxy phthalimide (NHPI). The present process is composed of a multistep sequence including a) formation of exo ‐cyclic enol ethers by dehydration; b) addition of phthalimide N ‐oxyl radical to the enol ethers followed by trapping of the resulting C‐radicals with molecular oxygen to form peroxy radicals; c) reductive generation of oxy radicals and subsequent β‐radical fragmentation to generate lactones. Abstract : Let′s get physical : A Cu‐catalyzed aerobic CC bond cleavage of cyclic hemiacetals (lactols) into lactones was achieved in the presence of N ‐hydroxy phthalimide (NHPI). This reaction is composed of a multistep sequence including a) formation of exo ‐cyclic enol ethers through dehydration; b) addition of phthalimide N ‐oxyl radical to the enol ethers followed by trap of the resulting C‐radicals with molecular oxygen to form peroxy radicals; c) reductive generation of oxy radicals and subsequent β‐radical fragmentation to generate lactones.