2-(Diphenylphosphino)biphenyl → (S)-3,4-dihydro-2,5,7,8-tetramethyl-2-vinyl-2H-[1]-benzopyran-6-ol

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Reaction Steps

A solution of (E)-5-(2,5-dihydroxy-3,4,6-trimethylphenyl)-3-methyl-2-pentenyl acetate (125 mg; 0.43 mmol), (R)-6,6'-dimethyl-2,2'-bis(diphenylphosphino-1,1'-biphenyl (7 mg, 3%) and π-allylpalladium chloride dimer (2.3 mg, 1.5%) in tetrahydrofuran (2 ml) was held at 65° C. for 12 hours. After cooling the solvent was removed and the residue was purified on 3 g of silica gel with hexane/ethyl acetate (99:1). After crystallization from pentane there was obtained 81 mg of (S)-3,4-dihydro-2,5,7,8-tetramethyl-2-vinyl-2H-[1]-benzopyran-6-ol. O.P. 53%.

Provenance & Evidence