Cyclohexanone cyanohydrin

When cyclohexanone is heated in the presence of a large amount of acetone cyanohydrin and a small amount of base, cyclohexanone cyanohydrin and acetone are formed. Propose a mechanism. 

Cyclohexanecarboxylic acid chloride, c351 Cyclohexaneethanol, c378 Cyclohexaneethyl acetate, c379 Cyclohexanemethanol, c384 Cyclohexanone cyanohydrin, hi 12 czis -4-Cyclohexene-l,2-dicarboximide, t82... 

Cyclohexanone cyanohydrin, hi 10 ds-4-Cyclohexene-1,2-dicarboximide, t75 ds-4-Cyclohexene-l,2-dicarboxylic anhydride, t74... 

Reports of five-membered ring formation involving this mechanism remain unauthenticated. Formation of an oxazolidinone product from Ritter reaction of cyclohexanone and cyclohexanone cyanohydrin has been shown by Ducker to result from an alternative pathway. Although 4-methyl-3-pentenonitrile did undergo intramolecular cyclization, this did not involve pyrrolidone formation. Rather a novel dimeric process took place, leading to formation of a monocyclic (74) and a bi-cyclic (75) product. The latter was readily ring opened to (74) using silver oxide and water (Scheme 37). 

---