I2-Promoted formal [3+2] cycloaddition of α-methylenyl isocyanides with methyl ketones: a route to 2,5-disubstituted oxazoles.
Xia WuXiao GengPeng ZhaoJingjing ZhangYan-Dong WuAn-Xin WuPublished in: Chemical communications (Cambridge, England) (2018)
An I2-promoted formal [3+2] cycloaddition for access to oxazoles has been demonstrated. This is the first example of a Lewis acid-promoted formal [3+2] cycloaddition of isocyanides with methyl ketones involving the C[triple bond, length as m-dash]N cleavage of isocyanides. The salient feature of this approach is unconventional 2,5-disubstituted oxazole formation from isocyanides and ketones rather than 4,5-substituted oxazoline.