0 Hits

  • Previous / Next

You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via Method 2: Cycloisomerization of Allenynes

DOI: 10.1055/sos-SD-046-00090

Gandon, V.; Thorimbert, S.; Malacria, M.Science of Synthesis, (200946231.

The cycloisomerizations of 1,7-allenynes in the presence of gold or platinum catalysts lead cleanly to either methylenecyclohexenes or vinylallenes depending upon the substituents and the solvent employed. For example, the use of gold(III) chloride allows the conversion of 1,7-allenyne 208, which has an internal alkyne unit, into 1,2,4-triene 209 at room temperature (Scheme 73).[‌178‌] The same reaction performed in methanol or an analogous experiment using the substrate 210, which bears a phenyl group at the internal allene position and yields the tricycle 211 (along with endocyclic dienes 212 and 213), provide evidence that carbocationic intermediates participate in such cyclizations.

Meeeee 88 Meee-Meeeeeeee Meeeeeeeeee ee 8,8-Meeeeeeee[‌888‌]