Iodine-Catalyzed Prins Cyclization of Homoallylic Alcohols and Aldehydes

Molecules

Kachi R. Kishore Kumar Reddy¹  Iara M. L. Rosa²  Antônio C. Doriguetto²  Erick L. Bastos¹ 

[1]Instituto de Química - Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, CP 26077, CEP 05513-970 São Paulo SP, Brazil

[2] E-Mails:

[3]Laboratório de Cristalografia, Instituto de Química, Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 714, 37130-000 Alfenas, Minas Gerais, Brazil

[4] E-Mails:

关键词: isochromene;    pyrans;    prins cyclization;    iodine;    DFT calculations;   

DOI  :  10.3390/molecules180911100

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.