Studies in the Baker-Venkataraman transformation. The Auwers synthesis of 2-acylcoumaran-3-ones

The Auwers synthesis of 2-acylcoumaran-3-ones (III) freom the corresponding o-acyloxy-ω-chloroacetophenones (I; X = CI) is shown almost certainly to involve an internal Claisen condensation of the Baker-Venkataraman type. This result confirms an earlier suggestion by Robertson and his collaborators (J., 1949, 562). Some quaternary chloride related to ω-chloro-acetophenones are described