Formation of 3,4-dimethyl-2-pyrones from allene carboxylates and 2-silyloxydienes via 3-carboethoxyethylidene cyclobutanols
作者:Michael E. Jung、Aaron R. Novack
DOI:10.1016/j.tetlet.2005.09.091
日期:2005.11
cyclobutanols 4 with various bases affords good yields of the substituted 3,4-dimethyl-2-pyrones 6. The proposed mechanisminvolvesringopening of the metal alkoxide 7 to give the carbanion 8, which undergoes proton transfer to give the more stable carbanion 9 and double bond isomerization to give the enolate 10, which then forms the pyrone ring 6 via attack on the ester via 11.