Triphenylphosphine → tert-butyl(dimethyl)silyl [(2R)-8-methoxy-3,4-dihydro-2H-chromen-2-yl]methyl ether

HRID 433145Notes

Reaction equation

HRID 433145 reaction equation
[Si:1]([O:8][CH2:9][C@@H:10]([OH:22])[CH2:11][CH2:12][C:13]1[CH:18]=[CH:17][CH:16]=[C:15]([O:19][CH3:20])[C:14]=1O)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OCC)=O)=NC(OCC)=O>C1(C)C=CC=CC=1>[CH3:20][O:19][C:15]1[CH:16]=[CH:17][CH:18]=[C:13]2[C:14]=1[O:22][C@@H:10]([CH2:9][O:8][Si:1]([C:4]([CH3:5])([CH3:6])[CH3:7])([CH3:2])[CH3:3])[CH2:11][CH2:12]2

Participants

5

Reactant 3

HCID 11776TriphenylphosphineHCID 220568ethyl N-ethoxycarbonyliminocarbamateHCID 114161542-((3S)-4-{[tert-butyl(dimethyl)silyl]oxy}-3-hydroxybutyl)-6-methoxyphenol

Product 1

HCID 11404073tert-butyl(dimethyl)silyl [(2R)-8-methoxy-3,4-dihydro-2H-chromen-2-yl]methyl etherYield 76%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

To a solution of 2-((3S)-4-{[tert-butyl(dimethyl)silyl]oxy}-3-hydroxybutyl)-6-methoxyphenol (6.90 g, 21.1 mmol) in toluene (250 mL) cooled to 0° C. was added triphenylphoshine (6.10 g, 23.2 mmol) followed by dropwise addition of diethyl azodicarboxylate (4.05 g, 23.2 mmol). The reaction mixture was allowed to stir at room temperature for 15 min. The reaction mixture was quenched by the addition of water (300 mL). The aqueous layer was separated and extracted with diethyl ether (2×150 mL). The combined organic extracts were washed with water (200 mL), aqueous sodium chloride (300 mL), dried (magnesium sulfate) and the solvent was removed in vacuo to give a crude oil. Purification by flash column chromatography (silica, ethyl acetate:hexanes 1:4) provided 4.94 g (76%, 40% ee) of tert-butyl(dimethyl)silyl [(2R)-8-methoxy-3,4-dihydro-2H-chromen-2-yl]methyl ether as a colorless oil. [α]D25=−25.84 (c 10.82 in chloroform, 40% ee); Rf=0.68 (silica, ethyl acetate:hexanes 1:4); Anal. Calcd. for C17H28O3Si.0.1 H2O: C, 65.8; H, 9.16. Found: C, 65.75; H, 8.88.

Workup

  1. customThe reaction mixture was quenched by the addition of water (300 mL)
  2. customThe aqueous layer was separated
  3. extractionextracted with diethyl ether (2×150 mL)
  4. washThe combined organic extracts were washed with water (200 mL), aqueous sodium chloride (300 mL)
  5. dry with materialdried (magnesium sulfate)
  6. customthe solvent was removed in vacuo
  7. customto give a crude oil
  8. customPurification by flash column chromatography (silica, ethyl acetate:hexanes 1:4)

Sources & evidence

ORD record
ord-bb9b6f888ba94800a8e215f3e94f4354
Source dataset
uspto-grants-2003_12
Patent number
US06667322B2

Reaction notes

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