Synthesis of conjugated polyenes via sequential condensation of sulfonylphosphonates and aldehydes.

Selective metalation of sulfonylphosphonates results in sufficiently stable carbanions that undergo chemoselective Julia-Kocienski condensation with various aldehydes to provide (E)-allylic phosphonates in good yields and selectivities. The subsequent Horner-Wadsworth-Emmons condensation with aldehydes is used to synthesize various unsymmetrical trans-dienes, trienes, and tetraenes. This methodology is utilized for the concise synthesis of a naturally occurring fluorescent probe for membrane properties, β-parinaric acid.