Uncommon aqueous media for nitrilimine cycloadditions. I. Synthetic and mechanistic aspects in the formation of 1-aryl-5-substituted-4,5-dihydropyrazoles
Oxygenated monoterpenes as dipolarophiles for nitrilimine cycloadditions
作者:Lara De Benassuti、Luisa Garanti、Giorgio Molteni
DOI:10.1016/j.tet.2004.03.077
日期:2004.5
A variety of naturally-occurring oxygenated monoterpenes, namely (S)-cis-verbenol, (1R)-(-)-myternol, (1S)-(-)-verbenone, (1R)-(-)-myternal, (S)-(-)-perillyl alcohol, and (S)-(-)-perillaldehyde have been submitted to nitrilimine cycloaddition. These processes were fully regio- and stereoselective for four dipolarophiles. In contrast, regioselective but non-stereoselective cycloadditions occurred in the case of two of the monoterpene derivatives. The configurations of the newly-formed stereocentres of the cycloadducts were assigned on the basis of NOE and NOESY experiments. (C) 2004 Elsevier Ltd. All rights reserved.