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

HRID 51666

Reaktionsgleichung

Reaktionsgleichung von HRID 51666
[CH2:1]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C([Li])CCC.[Br:26][C:27]1[CH:28]=[C:29]2[C:34](=[C:35]([CH:37]=O)[CH:36]=1)[O:33][C:32]([CH3:40])([CH3:39])[CH2:31][C:30]2([CH3:42])[CH3:41]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.CCCCCC>[Br:26][C:27]1[CH:28]=[C:29]2[C:34](=[C:35]([CH:37]=[CH2:1])[CH:36]=1)[O:33][C:32]([CH3:40])([CH3:39])[CH2:31][C:30]2([CH3:42])[CH3:41]

Komponenten

6

Edukt 3

HCID 137960MethylenetriphenylphosphoraneHCID 225689466-Bromo-2,2,4,4-tetramethyl chroman-8-carbaldehyde2×HCID 178418339Butyllithium

Produkt 1

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

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 74505Methyltriphenyliphosphonium bromideKatalysatorHCID 8058HexaneLösungsmittel

Versuchsvorschrift

A solution of methylidene triphenyl phosphorane [generated from methyl triphenylphosphonium bromide (7 g, 20 mmol) and (11.8 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%).

Aufarbeitung

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

Quellen und Nachweise

ORD-Eintrag
ord-a36b1875d1ba4772826b3056ecc53604
Quelldatensatz
uspto-grants-2004_03
Patentnummer
US06713647B2

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