‘Off-template site’ intramolecular nitrone cycloaddition (INC) reactions on sugar-derived allylic ethers—a study on the substituent effect and synthesis of furano-pyrans
作者:G.V.M Sharma、K Ravinder Reddy、A Ravi Sankar、A.C Kunwar
DOI:10.1016/s0040-4039(01)01889-5
日期:2001.12
Sugar-derived allylic ethers having one or two substituents on the terminal olefinic carbon centre were subjected to intramolecular nitrone cycloaddition (INC) reactions resulting in bicyclo[4.3.0] systems. The exclusiveness of product formation may be attributed to the effect of substituents.
Synthesis, high-resolution NMR spectroscopic analysis, and single-crystal X-ray diffraction of isoxazoline tetracycles
作者:Mirta L Fascio、Angel Alvarez-Larena、Norma B D'Accorso
DOI:10.1016/s0008-6215(02)00258-6
日期:2002.11
Three isoxazoline tetracycles were obtained enantiomerically pure by intramolecular 1,3-dipolar cycloaddition. The characterization of the new compounds was performed by high-resolution H-1 and C-13 NMR spectroscopy. The relative configuration of the new chiral centers was determined by NOESY experiments and confirmed by single-crystal X-ray structural analysis. (C) 2002 Elsevier Science Ltd. All rights reserved.