Methylenetriphenylphosphorane → 6-Bromo-8-vinyl-2,2,4,4-tetramethyl-chroman

HRID 844662Notes

Reaction equation

HRID 844662 reaction equation
[CH2:1]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C(OC(=O)C1C=CC(C#CC2C=CC3C(NC4CC4)CCC(C)(C)C=3C=2)=CC=1)C.C([Li])CCC.[Br:55][C:56]1[CH:57]=[C:58]2[C:63](=[C:64]([CH:66]=O)[CH:65]=1)[O:62][C:61]([CH3:69])([CH3:68])[CH2:60][C:59]2([CH3:71])[CH3:70]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.CCCCCC>[Br:55][C:56]1[CH:57]=[C:58]2[C:63](=[C:64]([CH:66]=[CH2:1])[CH:65]=1)[O:62][C:61]([CH3:69])([CH3:68])[CH2:60][C:59]2([CH3:71])[CH3:70]

Participants

7

Reactant 4

HCID 137960MethylenetriphenylphosphoraneHCID 129717084-(5-Cyclopropylamino-8,8-dimethyl-5,6,7,8-tetrahydro-naphthalene-2-ylethynyl)-benzoic acid ethyl esterHCID 225689466-Bromo-2,2,4,4-tetramethyl chroman-8-carbaldehyde2×HCID 178418339Butyllithium

Product 1

HCID 225689226-Bromo-8-vinyl-2,2,4,4-tetramethyl-chromanYield 72%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 8058HexaneSolvent

Procedure

A solution of methylidene triphenyl phosphorane [generated from methyl triphenylphosphonium bromide (7 g, 20 mmol) and (1 1.8 mL, 19 mmol) of a 1.6M solution of n-butyl lithium in hexanes ] was added 6-bromo-2,2,4,4-tetramethyl chroman-8-carbaldehyde (Intermediate 30, 0.52 g, 1.75 mmol). After 1 h the reaction mixture was diluted with hexane, washed with brine (×1), dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to a clear oil which was subjected to flash column chromatography over silica gel (230-400 mesh) using 2% ethyl acetate in hexane as the eluent to afford the title compound as a clear oil (0.37 g, 72%).

Workup

  1. washwashed with brine (×1)
  2. dry with materialdried over anhydrous sodium sulfate
  3. filtrationfiltered
  4. customevaporated in vacuo to a clear oil which

Sources & evidence

ORD record
ord-1d9e55a6b6534af383f139fb9c7b6b28
Source dataset
uspto-grants-2002_04
Patent number
US06380256B1

Reaction notes

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