Synthesis of Substituted 3-Iodocoumarins and 3-Iodobutenolides via Electrophilic Iodocyclization of Ethoxyalkyne Diols

Maddi Sridhar Reddy*, Nuligonda Thirupathi, Madala Hari Babu and Surendra Puri

*Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Chattar Manzil Palace, Lucknow-226 001, U.P., India, Email: msreddycdri.res.in

M. S. Reddy, N. Thirupathi, M. H. Babu, S. Puri, J. Org. Chem., 2013, 78, 5878-5888.

DOI: 10.1021/jo400499r

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Abstract

An exclusive 6-endo-dig iodocyclization of 3-ethoxy-1-(2-alkoxyphenyl)-2-yn-1-ols gives 4-substituted 3-iodocoumarins, whereas a 5-endo-dig iodocyclization of 1-alkoxy-4-ethoxy-3-yn-1,2-diols gives 3-iodobutenolides respectively. The reactions are carried out under very mild conditions using I₂ in DCM or toluene at room temperature.

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Key Words

Coumarins, Butenolides

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ID: J42-Y2013