Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes
Peihong Xiao, Zhixing Tang, Kai Wang, Hua Chen, Qianyou Guo, Yang Chu, Lu Gao* and Zhenlei Song*
*Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu 610064, P. R. China, Email: lugaoscu.edu.cn, zhenleisongscu.edu.cn
P. Xiao, Z. Tang, K. Wang, H. Chen, Q. Guo, Y. Chu, L. Gao, Z. Song, J. Org. Chem., 2018, 83, 1687-1700.
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In a sequential one-pot process for the conversion of sterically demanding N,N-diisopropylamides to aldehydes, amides are activated with EtOTf to form imidates, which are reduced with LiAlH(OR)3 [R = t-Bu, Et] to give aldehydes by hydrolysis of the resulting hemiaminals. The non-nucleophilic base 2,6-DTBMP remarkably improves reaction efficiency. The reaction tolerates various reducible functional groups, including aldehyde and ketone.
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proposed reaction mechanism