55-96% yields. The Friedel-Crafts reaction of alpha-(silyl)- or alpha-(germyl)phosphonoketene dithioacetals 2, 9, or 4 with acid chlorides gave alpha-acylated phosphonoketene dithioacetals 15-19 in 53-91% yields. The palladium-catalyzed cross-coupling reaction of beta-ethoxy-alpha-(tributylstannyl)vinylphosphonate 13 with a variety of organic halides (R = acyl, allyl, aryl, etc.) provided beta-ethoxy-alpha-substituted