Dehydration-type Ti-Claisen Condensation (Carbonhomologation) of α-Heteroatom-substituted Acetates with Alkyl Formates: Utilization as (<i>Z</i>
)-Stereodefined Cross-coupling Partners and Application to Concise Synthesis of Strobilurin A
homologation (dehydration type Ti-Claisen condensation) of alkyl α-heteroatom (halo and sulfonyloxy)-substituted acetates (XCH2CO2R) with alkyl formates (HCO2R) to afford various alkyl β-alkoxy-α-halo or sulfonyloxy-substituted acrylates (24 examples; 51%–91% yield). Stereoretentive Suzuki-Miyaura, Negishi, and Sonogashira cross-couplings using the obtained methyl β-methoxy-α-halo or sulfonyloxy-substituted