At the core of many of these projects are the 2-methyleneoxetanes 2 for which we have reported the first and, so far, only general synthesis. The utility and reactivity of 2 is derived from the strained nature of the oxetane ring and the exocyclic enol ether. For example, treatment of 2 with a strong base provides homopropargylic alcohols 3. On the other hand, reaction with a nucleophile, affords ß-substituted ketones 4. An alternative route to functionalized ketones is via arene-catalyzed, reductive ring opening of 2-methyleneoxetanes, providing 5. We also have reported the first synthesis of [2.2.0] fused ketals 6, and the first general syntheses of 1,5-dioxaspiro[3.2]hexanes 7 and 4-oxaspiro[2.3]hexanes 8.

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