Interception of Nazarov Reactions of Allenyl Vinyl Ketones with Dienes: (3+2)- versus (4+3)-Cycloaddition and Subsequent Rearrangement
作者:Timothy D. R. Morgan、François M. LeFort、Zhe Li、Vanessa M. Marx、Russell J. Boyd、D. Jean Burnell
DOI:10.1002/ejoc.201403618
日期:2015.5
Capture of the cyclic oxyallyl cation intermediates from the BF3-mediated Nazarov reactions of three allenyl vinyl ketones with various dienes was accomplished by (3+2)- and (4+3)-cycloaddition. The relative amounts of these types of products were dependent on the substitution on the diene, and this could be linked to steric hindrance. Treatment of the (3+2)-cycloadditionproducts with BF3·Et2O led mainly
Substituent-Controlled Reactivity in the Nazarov Cyclisation of Allenyl Vinyl Ketones
作者:Vanessa M. Marx、Rhonda L. Stoddard、Gavin S. Heverly-Coulson、D. Jean Burnell
DOI:10.1002/chem.201100519
日期:2011.7.11
also accelerates Nazarov cyclisation by increasing the population of the reactive conformer and by stabilising the oxyallyl cation intermediate. Furthermore, α substitution by an alkyl group does not alter the regioselectivity of interrupted Nazarov reactions when the oxyallyl cation intermediate is intercepted by addition of an oxygen nucleophile, or by [4+3] cyclisation with acyclic dienes. The regioselectivity