455258-25-0Relevant academic research and scientific papers
One pot synthesis of nitrogen-containing polycyclic δ-lactones by double nucleophilic addition of bis(trimethylsilyl)ketene acetals to pyridines
Rudler, Henri,Denise, Bernard,Parlier, Andree,Daran, Jean-Claude
, p. 940 - 941 (2002)
Pyridine and bis(TMS)ketene acetals (TMS = trimethylsilyl) react successively with methylchloroformate and iodine (or peracids) to give, via functionalized dihydropyridines, bicyclic nitrogen-containing lactones which have been characterized by X-ray crys
Bis(trimethylsilyl)ketene acetals as C,O-dinucleophiles: One-pot formation of polycyclic γ- and δ-lactones from pyridines and pyrazines
Rudler, Henri,Denise, Bernard,Xu, Yiming,Parlier, Andree,Vaissermann, Jacqueline
, p. 3724 - 3744 (2007/10/03)
Bis(trimethylsilyl)ketene acetals react with pyridines, quinoline and isoquinoline in the presence of stoichiometric amounts of methyl chloroformate to give the corresponding dihydropyridine-, dihydroquinoline- and dihydroisoquinoline-substituted carboxylic acids in satisfactory yields. The regio- and diastereoselectivities of the addition reactions, together with the presence or absence of rotamers, have been established. The isolated acids react with peracids to give β-hydroxy-δ-lactones through an intramolecular reaction. Similar lactonizations could also be brought about directly from the azaaromatic compounds in one-pot reactions with silica gel, iodine or bromine. In these cases δ-lactones or β-halo-δ-lactones were produced. The behaviour of pyrazines in these transformations is peculiar, since methyl chloroformate on its own induces the formation, through interaction with both nitrogen atoms, of polycyclic γ-lactones, a reaction formally reminiscent of the double nucleophilic addition of the same ketene acetals to (arene)tricarbonylchromium complexes. Most of the new structures were assigned through X-ray crystal structure determinations. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
