Synthetic Studies Pertaining to the 2,3-Pyridyne and 4,5-Pyrimidyne.

We report synthetic studies pertaining to two heterocyclic aryne intermediates: the 2,3-pyridyne and the 4,5-pyrimidyne. First, a 2,3-pyridyne precursor was readily accessed from 2-pyridone using a known procedure. Subsequently, 2,3-pyridyne generation and trapping were used to access several functionalized pyridines in a regioselective manner. In addition, we report synthetic routes to two isomeric silyltriflates, which were intended to serve as precursors to the 4,5-pyrimidyne. Consecutive 4,5-pyrimidyne generation and trapping experiments were ultimately deemed unfruitful. We expect these findings will promote the use of 2,3-pyridyne and other heterocyclic arynes as building blocks for the synthesis of functionalized heterocycles.