Lewis acid-promoted ketene-alkene [2 + 2] cycloadditions.
Described are the first examples of ketene-alkene [2 + 2] cycloadditions promoted by Lewis acids. Notable features of this method include (1) substantial rate acceleration relative to traditional thermal reactions, (2) good diastereoselectivities and yields for the formation of the cyclobutanone products, and (3) inverse diastereoselectivity compared with related thermal cycloadditions for many examples. These studies not only provide access to synthetically versatile cyclobutanones that cannot be prepared by traditional thermal cycloadditions but also address important mechanistic questions regarding ketene-alkene [2 + 2] cycloaddition reactions.
Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47401, United States.
Christopher M
CM
Rasik
M Kevin
MK
Brown
D000475:Alkenes / Q000737:chemistry*; D003500:Cyclization; D003503:Cyclobutanes / Q000138:chemical synthesis* / Q000737:chemistry; D058116:Lewis Acids / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D000475:Alkenes; D003503:Cyclobutanes; D058116:Lewis Acids