Ene-yne-ene and ene-yne-yne metathesis of norbornene derivatives
摘要:
Norbornene derivatives 4 and 5 containing sidechains bearing an internal alkyne and either a terminal alkene or a terminal alkyne were found to undergo a cascade of metathesis reactions when treated with ruthenium based metathesis catalysts to form highly functionalised pentacyclic products. The reactions illustrate an interesting difference in reactivity between Grubbs' catalyst and the second generation catalyst, with the former being more reactive for the early steps of the cascade. (C) 2003 Elsevier Ltd. All rights reserved.
Ene-yne-ene and ene-yne-yne metathesis of norbornene derivatives
摘要:
Norbornene derivatives 4 and 5 containing sidechains bearing an internal alkyne and either a terminal alkene or a terminal alkyne were found to undergo a cascade of metathesis reactions when treated with ruthenium based metathesis catalysts to form highly functionalised pentacyclic products. The reactions illustrate an interesting difference in reactivity between Grubbs' catalyst and the second generation catalyst, with the former being more reactive for the early steps of the cascade. (C) 2003 Elsevier Ltd. All rights reserved.
Ene–yne metathesis of polyunsaturated norbornene derivatives
作者:Donatella Banti、Elisabetta Groaz、Michael North
DOI:10.1016/j.tet.2004.06.114
日期:2004.9
Norbornene derivatives bearing endo-substituents in the 5- and 6-positions were studied as substrates for ene-yne metathesis cascades. Substrates which contained an internal alkyne and a terminal alkene or alkyne in each sidechain were found to undergo a metathesis cascade leading to pentacyclic bis-dienes and bis-trienes. Attempts to extend the chemistry further to sidechains containing two internal alkynes or two internal alkynes and a terminal alkene were not successful with the first generation Grubbs' catalyst. However, the substrate containing two internal alkynes did react with the second generation Grubbs' catalyst to give a tetra-diene containing product. (C) 2004 Elsevier Ltd. All rights reserved.