title: Iodine-catalyzed prins cyclization of homoallylic alcohols and aldehydes.
abstract: The iodine-catalyzed Prins cyclization of homoallylic alcohols and aldehydes was investigated under metal-free conditions and without additives. Anhydrous conditions and inert atmosphere are not required. The reaction of 2-(3,4-dihydronaphthalen-1-yl)propan-1-ol and 21 aldehydes (aliphatic and aromatic) in CH₂Cl₂ in the presence of 5 mol % of iodine gave 1,4,5,6-tetrahydro-2H-benzo[f]isochromenes in 54%-86% yield. Under similar conditions, the Prins cyclization of six alcohols containing an endocyclic double bond (primary, secondary, or tertiary) led to dihydropyrans in 52%-91% yield. The acyclic homoallylic alcohols gave 4-iodo-tetrahydropyran in 29%-41% yield in the presence of 50 mol % of iodine. This type of substrate is the main limitation of the methodology. The relative configuration of the products was assigned by NMR and X-ray analysis. The mechanism and the ratio of the products are discussed, based on DFT calculations.
authors.affiliation: Instituto de Química-Universidade de São Paulo, Av. Prof. Lineu Prestes 748, CP 26077, CEP 05513-970 São Paulo SP, Brazil.
authors.forename: Kachi R Kishore Kumar
authors.initials: KR
authors.lastname: Reddy
authors.forename: Iara M L
authors.initials: IM
authors.lastname: Rosa
authors.forename: Antônio C
authors.initials: AC
authors.lastname: Doriguetto
authors.forename: Erick L
authors.initials: EL
authors.lastname: Bastos
authors.forename: Luiz F
authors.initials: LF
authors.lastname: Silva
mesh_terms: D000438:Alcohols / Q000737:chemistry; D000447:Aldehydes / Q000737:chemistry; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D007455:Iodine / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011714:Pyrans / Q000138:chemical synthesis*; D011789:Quantum Theory; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D000447:Aldehydes; D011714:Pyrans; D007455:Iodine
references.citation: Org Lett. 2008 Jul 17;10(14):3101-4
references.pmid: 18543942
references.citation: Eur J Med Chem. 2012 Dec;58:1-11
references.pmid: 23085140
references.citation: J Org Chem. 2011 Mar 4;76(5):1499-502
references.pmid: 21244003
references.citation: Chem Commun (Camb). 2012 Jan 4;48(1):157-9
references.pmid: 22068454
references.citation: Angew Chem Int Ed Engl. 2010 Nov 2;49(45):8316-26
references.pmid: 20931580
references.citation: J Chem Inf Comput Sci. 2004 Nov-Dec;44(6):2133-44
references.pmid: 15554684
references.citation: Org Lett. 2009 Jan 15;11(2):357-60
references.pmid: 19093859
references.citation: J Am Chem Soc. 2006 Oct 18;128(41):13640-8
references.pmid: 17031979
references.citation: Angew Chem Int Ed Engl. 2012 May 29;51(22):5367-70
references.pmid: 22504783
references.citation: Org Lett. 2013 Feb 1;15(3):429-31
references.pmid: 23317410
references.citation: J Org Chem. 2008 Jan 18;73(2):741-4
references.pmid: 18095701
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677
references.citation: Chem Commun (Camb). 2012 Sep 25;48(74):9316-8
references.pmid: 22885680
references.citation: J Am Chem Soc. 2002 May 8;124(18):4960-1
references.pmid: 11982351
references.citation: Phys Rev Lett. 1996 Oct 28;77(18):3865-3868
references.pmid: 10062328
references.citation: Angew Chem Int Ed Engl. 2011 Dec 2;50(49):11598-620
references.pmid: 22113847
references.citation: Org Lett. 2013 Feb 1;15(3):546-9
references.pmid: 23339329
references.citation: Chemistry. 2008;14(35):11132-40
references.pmid: 18979467
references.citation: Org Lett. 2012 Jan 6;14(1):58-61
references.pmid: 22128826