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

HRID 1195479Notes

Reaction equation

HRID 1195479 reaction equation
C(O[CH2:5]/[CH:6]=[C:7](\[CH3:21])/[CH2:8][CH2:9][C:10]1[C:15]([CH3:16])=[C:14]([OH:17])[C:13]([CH3:18])=[C:12]([CH3:19])[C:11]=1[OH:20])(=O)C.C1(P(C2C=CC=CC=2C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>O1CCCC1>[CH3:21][C@@:7]1([CH:6]=[CH2:5])[CH2:8][CH2:9][C:10]2[C:15]([CH3:16])=[C:14]([OH:17])[C:13]([CH3:18])=[C:12]([CH3:19])[C:11]=2[O:20]1

Participants

4

Reactant 2

HCID 129769782-(Diphenylphosphino)biphenylHCID 19819049(E)-5-(2,5-dihydroxy-3,4,6-trimethylphenyl)-3-methyl-2-pentenyl acetate

Product 1

HCID 22843764(S)-3,4-dihydro-2,5,7,8-tetramethyl-2-vinyl-2H-[1]-benzopyran-6-olYield 81.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

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%.

Workup

  1. temperatureAfter cooling the solvent
  2. customwas removed
  3. customthe residue was purified on 3 g of silica gel with hexane/ethyl acetate (99:1)
  4. customAfter crystallization from pentane

Sources & evidence

ORD record
ord-4fde8453bc054a90a569bfabda358379
Source dataset
uspto-grants-1992_05
Patent number
US05110955

Reaction notes

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