GOLD-CATALYZED CYCLOISOMERIZATIONS OF FUNCTIONALYZED CYCLOPROPYL ALKYNES: THE CASES OF CARBOXAMIDES AND ALCOHOLS

J. FERNANDEZ-GARCÍA; H. A. GARRO; LAURA FERNÁNDEZ-GARCÍA; PATRICIA GARCÍA-GARCÍA; MANUEL FERNÁNDEZ-RODRÍGUEZ; ISABEL MERINO; ENRIQUE AGUILAR

ADVANCED SYNTHESIS & CATALYSIS (PRINT)

WILEY-V C H VERLAG GMBH

Año: 2017 vol. 359 p. 3035 - 3051

1615-4150

Push-pull alkynylcyclopropane derivatives are claimed as suitable and active substrates for gold-catalyzed transformations. Thus, 2(3H)-azepinones can be readily prepared from alkynylcyclopropanecarboxamides through a nucleophilic addition/cyclopropane ring-opening cascade process and, in this manuscript, the scope and the limitations of such reaction sequence are reported. The cascade reaction is general and occurs with complete regio- and quimioselection to form the seven-membered heterocycles with the exception of primary alkyl-substituted alkynylcyclopropanecarboxamides that render 4-methoxy-6-oxo-4-enenitriles in moderate yields. Additionally, less activated alkynylcyclopropylmethanols undergo regioselective cicloisomerization at low temperature leading to oxabicyclo[4.1.0]heptanes. Notably, the cyclopropane ring opening of these adducts takes place under thermal conditions to form dihydropyranones