Eighteen phosphorus-based alkenylation reagents 1a–6c were synthesized and condensed with n-butyraldehyde 7a and benzaldehyde 7f. They were condensed with the aldehydes 7b- e, gn to produce 2-methoxy-2-alkenoates 8a-n and 2-phenoxy-2-alkenoates 9a-n. A discussion on different selectivities for the alkenylation reagents under different experimental conditions (base, solvent, temperature), the influence of the aldehydes on ...