Reactions of Carbenes with Acetone. Reversible Thermal Formation and Fragmentation of Carbonyl Ylides and Their Cycloaddition to Acetone

Article abstract of DOI:10.1021/ja00343a035

2-Methoxy-2,5,5-trimethyl-Δ3-1,3,4-oxadiazoline (1) undergoes thermal decomposition in solution to form a carbonyl ylide intermediate.In acetone-d₆ a portion of the ylide is trapped by cycloaddition but a large fraction undergoes fragmentation, either to methyl acetate and 1-methylethylidene or to acetone and 1-methoxyethylidene.Both carbenes react with acetone-d₆ at the carbonyl oxygen to generate carbonyl ylides and they also insert into C-D bonds of the ketone.The carbonyl ylides themselves react with acetone by a 1,3-cycloaddition processes.