C. Walpole, Ziping Liu, Ernest E. Lee
Jun 13, 2012
Citations
0
Influential Citations
7
Citations
Journal
Tetrahedron Letters
Abstract
Abstract A diastereoselective synthesis of fluoropiperidine quinazoline spirocycles has been developed through a silyl triflate mediated intermolecular coupling of difluorobenzamidine and racemic N-protected 3-fluoropiperidine dimethyl ketals or piperidones. Combination of the silyl reagents together with Lewis acids (such as BF 3 ·OEt 2 , ZnCl 2 , InCl 3 , etc.) accelerated the coupling reaction to afford the desired fluorospirocycles in good yields (40–83%) and high diastereoselectivity. A ratio of the two diastereoisomers of up to 10:1 in favor of the desired isomer can be achieved.