Stereoselective Synthesis of 2-(4-Hydroxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-aldehyde—The Key Intermediate of Sinaiticin

2-(4-Hydroxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-aldehyde 8,the key intermediate of sinaiticin 10,was synthesized in 6 step from caffeic acid 4 and 4- hydroxybenzsaldehyde 1.the coupling reaction is the key step.