Reaction of Dicarbomethoxycarbene with Acetaldehyde and Simple Ketones

Article abstract of DOI:10.1021/ja00209a034

Singlet dicarbomethoxycarbene reacts with acetaldehyde to give dioxolane 8, the ultimate product of formation of ylide 10 and subsequent addition of a second molecule of aldehyde.Photosensitized generation of the carbene gives increased hydrogen abstraction and decreased products derived from the ylide.Replacement of the aldehyde with a ketone changes the course of the reaction and dioxolanes (11, 20, and 26) become the major products.Suggestions are made for the mechanisms of the singlet and triplet reactions and for the peculiar behavior of acetone in which generation of singlet and triplet carbene gives the same product slate.