Health & Environmental Research Online (HERO)


Print Feedback Export to File
8337074 
Journal Article 
Axial-selective prins cyclizations by solvolysis of α-bromo ethers 
Jasti, R; Vitale, J; Rychnovsky, SD 
2004 
Yes 
Journal of the American Chemical Society
ISSN: 0002-7863
EISSN: 1520-5126 
126 
32 
9904-9905 
English 
Prins cyclizations are intramolecular electrophilic additions of oxocarbenium ions. They lead to tetrahydropyrans with a heteroatom at the 4-position, and usually show moderate-to-high selectivity for equatorial substitution. We have found that Prins cyclizations carried out under specific conditions produce tetrahydropyrans with almost exclusive formation of the axial 4-substituent. TMSBr, AcBr, and TMSI all lead to axial-selective Prins cyclizations with α-acetoxy ether substrates in the presence lutidine. The mechanism appears to involve solvolysis of the intermediate α-bromo ether rather than specific or Lewis acid-catalyzed rearrangement. The scope of the reaction, the high yields, and the stereoselectivity make this a valuable new method for tetrahydropyran formation. Copyright © 2004 American Chemical Society.