cs5012519_si_003.cif (31.55 kB)
Catalytic Copper-Mediated Ring Opening and Functionalization of Benzoxazoles
dataset
posted on 2014-11-07, 00:00 authored by Macarena Corro, Maria Besora, Celia Maya, Eleuterio Álvarez, Juan Urbano, Manuel R. Fructos, Feliu Maseras, Pedro J. PérezA novel
reaction involving benzoxazole, ethyl diazoacetate, and
water has been discovered, with TpBr3Cu(NCMe) (TpBr3 = hydrotris(3,4,5-tribromopyrazolyl)borate) as the catalyst. The
fused azoles are converted into highly functionalized substituted
benzenes bearing aldehyde, amine carboxylate and hydroxyl groups.
The protocol has been applied for a series of benzoxazoles with several
diazo compounds. Experimental data and theoretical calculations have
led to a mechanistic proposal that includes carbene addition, ylide
formation, and water addition to the latter, all those steps being
catalyzed by the copper center.