N-Acylphthalimides represent an underutilized functional group in organic chemistry. We have found that aldehydes “insert” into the N-acyl bond of N-acylphthalimides to give N-phthalimido-O-acyl-N,O-acetals. The optimized conditions include use of a lithium cation and tertiary amine. The reaction occurs quickly at room temperature and minimal purification is required. The scope of N-acylphthalimide and aldehyde reactants is broad and a myriad of N,O-acetals can be prepared. Additionally, in the presence of a Lewis acid, the resulting N,O-acetals generate phthaloyl iminium ion intermediates, which can further react with π-donors to form a carbon-carbon bond. Because the phthalimide can be readily removed, the overall process represents a unique strategy for preparing α-branched primary amines. Studies related to reaction optimization, scope evaluation, and mechanism of the overall transformation will be presented.

Synthesis of N-phthalimido-O-acyl-N,O-acetals from aldehydes and their conversion into α-branched phthalimides

249th National Meeting (2015)

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