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Fluorination-Free Synthesis of a 4,4-Difluoro-3,3-Dimethylproline Derivative

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posted on 21.07.2006 by Lijian Chen, Young Mi Kim, David J. Kucera, Katheryn E. Harrison, Sogole Bahmanyar, Jill M. Scott, Daniel Yazbeck
A Claisen rearrangement/iodolactamization sequence starting from commercially available trifluoroacetaldehyde methyl hemiacetal, followed by a classical chemical resolution, provided enantiomerically pure 4,4-difluoro-3,3-dimethylproline (S)-1. No hazardous fluorination reagents were used, and the overall yield over 12 steps was greater than 28%.