Potassium Phosphate, Tribasic → methyl 2-[2(3-[(2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-[(benzyloxy)methyl]tetrahydro-2H-pyran-2-yl]phenyl)ethyl]azulene-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A THF solution (8.0 ml) of 9-borabicyclo[3.3.1]nonane was added to (1S)-1,5-anhydro-2,3,4,6-tetra-O-benzyl-1-(3-vinylphenyl)-D-glucitol (1.0 g) and the mixture was refluxed with heating for four hours. Next, a 3 M aqueous solution of potassium phosphate (1.3 ml) and DMF (12 ml) were added to the reaction mixture. Methyl 2-chloroazulene-1-carboxylate (0.35 g) and 1,1′-diphenylphosphinoferrocene dichloropalladium (II) (0.12 g) were further added to the mixture, followed by stirring at 50° C. for two hours. After cooling to room temperature, the reaction mixture was poured into ice-cooled water and extracted with ethyl acetate. The organic layer was washed with saturated aqueous solution of sodium hydrogencarbonate and saturated brine in that order and dried over anhydrous sodium sulfate. The reaction mixture was concentrated. The residue was purified by silica gel column chromatography (n-hexane-ethyl acetate) to obtain methyl 2-[2(3-[(2S,3S,4R,5R,6R)-3,4,5-tris(benzyloxy)-6-[(benzyloxy)methyl]tetrahydro-2H-pyran-2-yl]phenyl)ethyl]azulene-1-carboxylate (0.88 g).

Provenance & Evidence