Weinreb Amides in Carbene Chemistry: A Time-Resolved IR Investigation into a Potential Intramolecular Stabilization Mechanism

A chloromethylhydroxamiccarbene was generated photochemically in an attempt to form an intramolecularly stabilized carbene. A rapidly formed intermediate at 1645 cm−1 decayed with an observed rate of 1.99 × 106 s−1. Other intermediates were also observed. These also decayed, albeit much more slowly (k obs = 3.47 × 103 and 1.98 × 104 s−1). Multiple intermediates are apparently a function of both the proximal N,O-dimethylhydroxamic ester and multiple conformers of both the carbene and precursor.