O-Heterocycles by the cyclization of side-chain bromomethoxylated 2?-acetoxychalcones
摘要:
The title chalcone derivatives react with aqueous sodium hydroxide of various concentrations to form aurones as the major product, together with small amounts of flavones. However, the introduction of 4'-nitro or 4'-chloro substituents resulted in the formation of flavones as the major product.
An efficient and facile two-step strategy for the synthesis of (Z)-aurone from arylacetylenes and salicyladehydes, via silver(I) nitrate mediated cyclization/oxidation in the presence of potassium carbonate has been developed. The key feature of our method was delicate cascade reaction, to provide the corresponding (Z)-aurone in high yield and good regio- and stereo selectivity.
Preparative and regiochemical aspects of the palladium-catalyzed carbonylative coupling of 2-hydroxyaryl lodides with ethynylarenes
作者:Pier Giuseppe Ciattini、Enrico Morera、Giorgio Ortar、Sabina Strano Rossi
DOI:10.1016/s0040-4020(01)86572-8
日期:1991.8
The title reaction has been conveniently carried out in DMF at 60-degrees-C under 1 atm of CO pressure using DBU as the base and Pd(OAc)2(DPPF)2 as the catalyst to afford generally mixtures of flavones 4 and aurones 5 in varying yields, depending on the substituents in the both reactants. Factors controlling the regioselectivity for 4 or 5 formation in this and in similar, previously reported, coupling procedures have been examined.
v. Auwers; Pohl, Justus Liebigs Annalen der Chemie, 1914, vol. 405, p. 291
作者:v. Auwers、Pohl
DOI:——
日期:——
TAKEUCHI, YASUO;CHOSHI, TOMINARI;TOMOZANE, HIDEO;YOSHIDA, HIROKAZU;YAMATO+, CHEM. AND PHARM. BULL., 38,(1990) N, C. 2265-2267