Gold(I) catalysed cycloisomerisation of β-hydroxy propargylic esters to dihydropyrans/2H-pyrans via allene intermediates
作者:Ramesh Kotikalapudi、K.C. Kumara Swamy
DOI:10.1016/j.tet.2013.07.003
日期:2013.9
Efficient cycloisomerisation of β-hydroxy propargylic esters to dihydropyrans/2H-pyrans via 1,3-carboxylate migration followed by regioselective hydroxyl addition to the transient allene intermediate catalysed by Ph3PAuCl/AgSbF6 is presented. Similar reactions on phosphorylated precursors led to phosphono-furans and phosphono-pyrans. In a few cases, self-condensation of β-hydroxy propargylic esters
An efficient and convenient synthesis of advanced (highly functionalized) tricyclic frame works present in the isofuranonaphthalenone, nodulones A-C and xestolactone A natural products has been achieved. The dehydro Diels-Alder reaction was employed as the key step for the construction of tricyclic systems.
Palladium-Catalyzed Cross-Coupling of 2,5-Cyclohexadienyl-Substituted Aryl or Vinylic Iodides and Carbon or Heteroatom Nucleophiles
作者:Richard C. Larock、Xiaojun Han
DOI:10.1021/jo981876f
日期:1999.3.1
most cases, this process is highly diastereoselective. The reaction is believed to proceed via (1) oxidative addition of the aryl or vinyliciodide to Pd(0), (2) organopalladium addition to one of the carbon-carbon double bonds, (3) palladium migration along the carbon chain on the same face of the ring to form a pi-allylpalladium intermediate, and (4) nucleophilic displacement of the palladium.
Dual catalysis by Cu(i): facile single step click and intramolecular C–O bond formation leading to triazole tethered dihydrobenzodioxines/benzoxazines/benzoxathiines/benzodioxepines
作者:M. Nagarjuna Reddy、K. C. Kumara Swamy
DOI:10.1039/c3ob41332b
日期:——
involving two different reactions, click (alkyne–azide) and carbon–oxygen bond formation (aryl iodide–secondary alcohol) in a single step, is reported. Synthesis of novel benzodioxines (benzodioxanes), benzoxazines, benzoxathiines and benzodioxepines, which feature benzo-condensed six or seven membered rings containing two hetero-atoms attached to a 1,2,3-triazole, is described. As an extension, such compounds
Gold(III) Bromide Catalyzed Furannulation of 2-Alkynylcycloalk-2-enols: An Expedient Route to Fused Furans
作者:P. Perumal、C. Praveen、P. Kiruthiga
DOI:10.1055/s-0029-1217517
日期:2009.7
An efficient synthesis of fused furans from 2-alkynylcycloalk-2-enols via gold(III) bromide catalyzed cycloisomerization was achieved. The reaction condition is moderate and amenable to structurally diverse substrates, leading to good yield of products.