The cycloaddition of di~ henylketene~ and diniethylketene4 to vinyl ethers was first noted by Staudinger in 1920. A few years ago, Hurd and Kinibrough reexamined the cycloadduct of diphenylketene and ethyl vinyl ether, and corrected Staudinger's original structural assignment by demonstrating that the product was 3-ethoxy-2, 2-diphenylcyclobutanone (Ia). 5 They also prepared and characterized the corresponding cycloadducts, IIa and IIb, ...
