Fragmentation involving formation of enamine
@Laura: Both Waylander and Zhe are correct in their respective comments. Your example is from the work of Hendrickson and Boeckman.1 Enamine 1 and conjugated aldehyde 2 were mixed neat forming bridged aminoketone 3. At some point, as Zhe has intimated, exchange of pyrrolidine from the ketone to the aldehyde must occur before cyclization to 3 can be accomplished. The usual explanation is that traces of water are present to catalyze the reaction. Quaternization of the amino group in 3 affords the salt 4 which cleaves with hydroxide via a Grob-like fragmentation to 5. Note the important anti arrangement of the dotted bond and the proximate vicinal bold bond. The product contains a double bond as Waylander has stated. The first example of this reaction, 6 --> 9, was reported by Stork and Landesman2 in 1956.


1) J. B. Hendrickson and R. K. Boeckman, Jr., J. Am. Chem. Soc., 1971, 93, 1307.
2) G. Stork and H. K. Landesman, J. Am. Chem. Soc., 1956, 78, 5129.