Iron(III)-catalyzed Prins-type cyclization using homopropargylic alcohol: a method for the synthesis of 2-alkyl-4-halo-5,6-dihydro-2H-pyrans

Pedro O Miranda; David D Díaz; Juan I Padrón; Jaime Bermejo; Victor S Martín

doi:10.1021/ol034568z

Iron(III)-catalyzed Prins-type cyclization using homopropargylic alcohol: a method for the synthesis of 2-alkyl-4-halo-5,6-dihydro-2H-pyrans

Org Lett. 2003 May 29;5(11):1979-82. doi: 10.1021/ol034568z.

Authors

Pedro O Miranda¹, David D Díaz, Juan I Padrón, Jaime Bermejo, Victor S Martín

Affiliation

¹ Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, C/Astrofísico Francisco Sánchez 2, 38206 La Laguna, Tenerife, Spain.

PMID: 12762701
DOI: 10.1021/ol034568z

Abstract

[reaction: see text] A new Prins-type cyclization between homopropargylic alcohol and aldehydes in the presence of FeX(3) to obtain 2-alkyl-4-halo-5,6-dihydro-2H-pyrans in good yield is described. Osmium-catalyzed cis dihydroxylation provided direct access to trans-2-alkyl-3-hydroxy-tetrahydro-pyran-4-ones. Anhydrous ferric halides are also shown to be excellent catalysts for the standard Prins cyclization using homoallylic alcohol. Isolation of an intermediate acetal provides substantiation of a proposed mechanism.