作者:Virtudes Pardo-Rodríguez、Elena Buñuel、Daniel Collado-Sanz、Diego J. Cárdenas
DOI:10.1039/c2cc34468h
日期:——
Reaction of a variety of 1,7-enynes with bis(pinacolato) diboron catalysed by Pd bis(trifluoroacetate) affords homoallylic and allylic boronates containing a six membered carbo- or heterocycle, by formation of C–C and C–B bonds
Oxidative intramolecular [4 + 2]cycloaddition of silylene-protected 2-pyridone derivatives—a short and efficient synthesis of the DEF-ring of fredericamycin A
Thermal treatment of 2-pyridone derivatives 2 with dimethyldichlorosilane, triethylamine and chloranil in benzene gives 8-hydroxyisoquinolones 4 in high yields by oxidative intramolecular [4 + 2]cycloaddition which are used in the synthesis of the fully functionalized DEF-ring 14 of fredericamycin A.
Thermal [2+2] Cycloaddition of Allenynes: Easy Construction of Bicyclo[6.2.0]deca-1,8-dienes, Bicyclo[5.2.0]nona-1,7-dienes, and Bicyclo[4.2.0]octa-1,6-dienes
the allenyl group, in xylene (or mesitylene) without microwave irradiation resulted in the efficient formation of bicyclo[5.2.0]nona-1,7-dienes and bicyclo[4.2.0]octa-1,6-dienes in high yields. This method was shown to be successfully applicable to the first construction of bicyclo[6.2.0]deca-1,8-dienes. Construction of the corresponding oxa- and azabicyclo[m.2.0] frameworks could also be attained.
A Cascade Palladium-Mediated Cross-Coupling/Electrocyclization Approach to the Construction of Fused Bi- and Tricyclic Rings
作者:S. B. Jennifer Kan、Edward A. Anderson
DOI:10.1021/ol8007952
日期:2008.6.5
A versatile palladium-catalyzed cyclization/cross-coupling/electrocyclization strategy for the synthesis of fused bi- and tricyclic ring systems is described. Excellent yields of the polycyclic products are obtained with a range of tethering ring sizes and functionality, including an unprecedented 5,6,4,5-fused tetracycle. The reaction mechanism features two unusual palladium-mediated isomerizations