87869-51-0Relevant articles and documents
Aerobic synthesis of pyrroles and dihydropyrroles from imines: Palladium(II)-catalyzed intramolecular C-H dehydrogenative cyclization
Shi, Zhuangzhi,Suri, Mamta,Glorius, Frank
supporting information, p. 4892 - 4896 (2013/06/04)
sp3ectacularly mild! An efficient PdII-catalyzed intramolecular dehydrogenative cyclization of imines affords (dihydro)pyrrole products using molecular oxygen as the sole oxidant. This mild formal sp 3-C-H functionalization allows rapid and atom-economical assembly of (dihydro)pyrrole rings from inexpensive and readily available allylamines and ketones. A broad range of functional groups are tolerated. Copyright
Thermal Electrocyclic Reactions of 2-Aza-1,3-butadiene Derivatives. A New N-Heterocyclic Annelation
Govindan, C. K.,Taylor, Grant
, p. 5348 - 5354 (2007/10/02)
A general, three-step annelation sequence, which ultimately gives 3,4-dihydro-2-quinolines and related derivatives (3), is described.The cyclization step is accomplished by pyrolysis of a 1-arenyl-2-aza-1,3-butadiene analogue (2) that apparently undergoes successive six-?-electron electrocyclization and 1,5-hydrogen migration reactions to yield the product.The conjugated azadienes, 2, are prepared by the base-catalyzed isomerization of the unconjugated isomers, 1.Compounds 1 are prepared by condensing arenyl ketones or aldehydes with 2-propenyl-1-amine.Steric effects of substituents on the azadiene chain and steric and electronic effects of the arenyl group on the cyclization step were studied.The following general conclusions were drawn: alkyl substituents R on the C=N terminus of 2 hinder a competing degradative process (commencing with a four-?-electron electrocyclization) and improve the yield of products 3; electron-withdrawing substituents on Ar of 2 or electron-withdrawing Ar groups enhance the yield of cyclized products, but they impart little regioselectivity to the reaction; regioselectivity may be imparted by ? bond fixation in Ar; electrocyclization also proceeds well with ?-electron excessive Ar groups on 2.The preferred conformation of the heterocyclic product 3 can be readily deduced by 1H NMR spectroscopy.