The gold-catalyzed oxidation of N-tosyl-protected 6-alkynyl-3,4-dihydro-2H-pyridines was studied in detail to obtain divinyl ketones in which one of the double bond is embedded in a heterocyclic framework. The best reaction conditions were then extended to different types of substrates to assess the scope of the reaction. DFT calculations were exploited to gain insight into the regioselectivity and
A Palladium-Catalyzed Three-Component Cross-Coupling of Conjugated Dienes or Terminal Alkenes with Vinyl Triflates and Boronic Acids
作者:Longyan Liao、Ranjan Jana、Kaveri Balan Urkalan、Matthew S. Sigman
DOI:10.1021/ja201358b
日期:2011.4.20
A three-component coupling of vinyl triflates and boronic acids to alkenes catalyzed by palladium is reported. Using 1,3-dienes, selective 1,2-alkene difunction-alization is observed, whereas the use of terminal alkenes results in 1,1-alkene difunctionalization. The reaction outcome is attributed to the formation of stabilized, cationic Pd-π-allyl intermediates to regulate β-hydride elimination.
Stereoselective Synthesis of Spirocyclic Ketones by Nazarov Reaction
作者:Cristina Prandi、Annamaria Deagostino、Paolo Venturello、Ernesto G. Occhiato
DOI:10.1021/ol051464a
日期:2005.9.1
[reaction: see text] The Suzuki-Miyaura cross-coupling reaction between alpha-ethoxydienyl boronates and lactone-derived vinyl triflates affords functionalized 6-(1-ethoxy-1,3-butadienyl)dihydropyran derivatives that undergo a Nazarov electrocyclic reaction under mild acidic conditions to give functionalized spirocyclic ketones. The product distribution and the stereoselectivity of the process are
A new class of conjugated strigolactone analogues with fluorescent properties: synthesis and biological activity
作者:Chaitali Bhattacharya、Paola Bonfante、Annamaria Deagostino、Yoram Kapulnik、Paolo Larini、Ernesto G. Occhiato、Cristina Prandi、Paolo Venturello
DOI:10.1039/b907026e
日期:——
A new class of strigolactoneanalogues has been synthesized. They differ from known molecules, both of natural and synthetic origin, in two main features. The conjugated system extends from the enol ether bridge to the A ring, the B ring is a heterocycle while the C ring is a cyclic ketone instead of a γ-lactone. The key step of the synthesis is a Nazarov cyclization on activated substrates. Bioassays
Synthesis of Weinreb Amides via Pd-Catalyzed Aminocarbonylation of Heterocyclic-Derived Triflates
作者:A. Deagostino、Paolo Larini、Ernesto G. Occhiato、Lorena Pizzuto、Cristina Prandi、Paolo Venturello
DOI:10.1021/jo7024898
日期:2008.3.1
lactone-, and thiolactone-derived triflates into N-methoxy-N-methyl or morpholine Weinreb amides has been realized using Pd-catalyzed aminocarbonylation under CO atmospheric pressure and at room temperature. The carbonylative coupling can be efficiently carried out with 2% of catalyst in the presence of Xantphos as a ligand. The amides smoothly react with nucleophiles to afford acylated aza-, oxa-, and