3-Fluoro-3-buten-2-one (2) is readily prepared from 1-fluoro-l-chloro-2-methoxy-2-methylcyclopropane (1) in 82% yield by heating the cyclopropane in aqueous quinoline solution. Ketone 2 reacts with aryl iodides (3) in a Heck reaction catalyzed by Pd(OAc)(2) to give Z-3-fluorobenzalacetones (4) in 36-86% yield. (C) 2008 Elsevier B.V. All rights reserved.