Study of<i>cis/trans</i>and<i>endo/exo</i>Diastereoselectivity in the [4+3]-Cycloaddition Reaction of 2-Functionalized Furans and Dimethyloxyallyl Cation: Preparation of Versatile Cycloheptane Synthons
作者:Angel M. Montaña、Sandra Ribes、Pedro M. Grima、Francisca García
DOI:10.1246/cl.1997.847
日期:1997.9
A study on the influence of steric and electronic effects of a function attached at C-2 of furans in the yield and diastereoselectivity of [4+3] cycloaddition reactions with oxyallyl cations is presented. In almost all studied furans a cis diastereospecificity and a high endo diastereoselectivity is observed. Increasing bulkyness of the function attached at C-2 of furans, increases the endo diastereoselectivity, but decreases yield. Increasing the electronic density of the furan system, by an electron donating group attached at C-2, increases yield and diastereoselectivity.
Complete assignment of1H and13C NMR data and establishment of the relative stereochemistry of C-1-functionalized 2,4-dimethyl-8-oxabicyclo[3.2.1] oct-6-en-3-one derivatives
作者:Angel M. Montaña、Pedro M. Grima、Francisca García
The total assignment of the 1H and 13C NMR spectra of 24 cis‐endo and 15 cis‐exo diastereoisomers of C‐1‐substituted 2,4‐dimethyl‐8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐one derivatives was deduced from the concerted application of DEPT, COSY, HETCOR, HMBC, HMQC and PS‐NOESY experiments. The relative stereochemistry of major (cis‐endo) and minor (cis‐exo) diastereoisomers was established on the basis of correlation
The first synthesis of nostoclideI (1a) and II (1b) has been accomplished in a concise, fully regio- and stereocontrolled manner by sequential 2,3,4-trisubstitution of butenolide (6) using 2-furanolates as key intermediates.
(DE) Die vorliegende Erfindung betrifft neue substituierte bicyclische Lactone, Verfahren zu ihrer Herstellung und ihre Verwendung zur Prävention und/oder Behandlung von Erkrankungen, die durch eine Über- oder Unterfunktion des glutamatergen Systems ausgelöst werden, insbesondere von cerebralen Ischämien, Schädel-/Hirntrauma, Schmerzzuständen oder ZNS-vermittelten Krämpfen.(EN) The invention relates to novel substituted bicyclic lactones, to methods for producing said substituted bicyclic lactones, and to their use for preventing and/or treating diseases caused by the hyper- or hypofunction of the glutamatergic system, especially cerebral ischaemia, cranial/cerebral trauma, pain or CNS-mediated cramps.(FR) L'invention concerne de nouvelles lactones bicycliques substituées, leurs procédés de production et leur utilisation pour prévenir et/ou traiter des maladies provoquées par une hyperfonction ou une hypofonction du système glutamatergène, notamment les ischémies cérébrales, les traumatismes crâniens/cérébraux, les douleurs ou les crampes induites par le SNC.
2-Functionalized furans as precursors of versatile cycloheptane synthons
作者:Angel M. Montaña、Sandra Ribes、Pedro M. Grima、Francisca García、Xavier Solans、Mercè Font-Bardia
DOI:10.1016/s0040-4020(97)00739-4
日期:1997.8
An study on the influence of steric and electronic effects of a function attached at C-2 of furans in the yield and diastereoselectivity of [4+3] cycloaddition reactions with oxyallyl cations is presented. In almost all studied furans a cis diastereospecificity and a high endo diastereoselectivity is observed. Increasing bulkyness of the function attached at C-2 of furans, the endo diastereoselectivity increases, but yield decreases. Increasing the electronic density of the furan system, by an electron donating group at C-2, both yield and diastereoselectivity increase. (C) 1997 Elsevier Science Ltd.