Synthetically appealing transformations based on chlorinated ketenes continue to be uncovered in spite of the nearly 35 years that have elapsed since their initial preparation.  We have been most interested in recent years in developing a diastereofacially selective 2+2 cycloaddition reaction of these ketenes with chiral olefins to generate chlorinated cyclobutanones in high diastereomeric excess, and in exploiting the rich chemistry of these cycloadducts.