Approaches to oximidines, lobatamides and related natural products: the coupling reactions of 3-iodoacrolein O-methyl oximes

Both 2E- and 2Z-3-iodoacrolein O-methyl oximes are prepared in two steps from ethyl propiolate. Lithium–iodine exchange is effected and the resulting organolithium reagents added to several electrophiles, including styryl isocyanate which gives a conjugated O-methyl oxime enamide of the type found in the side chains of the oximidine, lobatamide and CJ-12950 natural products. The Pd(0) catalysed cross-coupling of these iodoalkenes is also explored.