Synthesis of the seed germination stimulant 3-methyl-2H-furo[2,3-c]pyran-2-ones utilizing direct and regioselective Ti-crossed aldol addition

3-Methyl-2H-furo[2,3-c]pyran-2-ones 1 and 2, a unique and remarkable seed germination stimulant, and its analogue were synthesized using direct and regioselective Ti-crossed aldol addition between dihydro-2H-pyran-3(4H)-ones and methyl pyruvate as the key step, followed by furanone formation.