Ring-Closing Metathesis Approach to 2H-2-Benzazepine-l,3-diones

摘要

A series of diversely substituted 2H-2-benzazepine-l,3-diones were efficiently prepared from the unsaturated precursors, N-acyl-o-vinylbenzamides, through a ring-closing metathesis reaction. The parent compounds were easily obtained from the appropriate o-vinylbenzoic acids.Benzo-fused heterocyclic ring systems have received a lot of attention over the years because of their ubiquitous appearance in natural products and modern pharmaceuti-cals.1 2-Benzazepines and their oxo derivatives at different oxidation levels fall into this category. They are a class of benzo-fused nitrogen-containing seven-mem-bered heterocyclic rings, which are important structural features of marketed drugs, clinical candidates, and other bioactive molecules.2 As a consequence, the development of synthetic methodologies that may have generality for the construction of multifarious substituted and unsubsti-tuted benzazepines is an area of current interest and alternative methods are currently the object of synthetic endeavor. In this context we envisioned the assembly of the corresponding a,p-unsaturated oxobenzolactams, that is, the 2H-2-benzazepine-l,3-diones la-f (Figure 1).