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22nd August 2013 @ 09:06

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Reaction information

*#Reaction file  
CSRxnsScheme_78.cdx
*Reaction file type CDX
*Procedure   DMSO (0.32 mL, 4.5 mmol) in dry DCM (1.00 mL) was added dropwise to oxalyl chloride (0.19 mL, 2.2 mmol) in dry DCM (5.0 mL) at −60 °C.  The reaction mixture was stirred at −60 °C for 2 mins.  2-(Oct-3-ynyl)dec-5-yn-1-ol (531 mg, 2.0 mmol) in dry DCM (2.0 mL) was added dropwise to the reaction mixture at −60 °C.  The reaction mixture was stirred at −60 °C for 15 mins.  Et3N (1.40 mL, 10.1 mmol) was added dropwise to the reaction mixture.  The reaction mixture was stirred at −60 °C for 15 mins followed by stirring at room temperature for 1 h.  The reaction mixture was poured into water (50 mL) and extracted with DCM (2 × 25 mL).  The organic extracts were combined, washed sequentially with brine (50 mL), 1% aq. HCl solution (2 × 25 mL), water (50 mL) and 5% aq. Na2CO3 solution (50 mL), dried (MgSO4), filtered and the solvent removed in vacuo to give the crude intermediate 2-(oct-3-yn-1-yl)dec-5-ynal as a pale yellow oil (470 mg).  n‑BuLi (1.12 mL of a 2.5 M solution in hexanes, 2.8 mmol) was added dropwise to methyltriphenylphosphonium bromide (1.00 g, 2.8 mmol) in dry THF (10.0 mL) at −20 °C and left stirring at this temperature for 30 mins.  The reaction mixture was cooled to −78 °C.  Intermediate 2-(oct-3-yn-1-yl)dec-5-ynal (370 mg, 1.4 mmol) was added dropwise to the reaction mixture at −78 °C and the reaction mixture stirred at this temperature for 30 mins.  The reaction mixture was then stirred at room temperature for 45 mins, poured into a cold sat. aq. NH4Cl solution (50 mL) and extracted with ether (3 × 30 mL).  The organic extracts were combined, washed with brine (2 × 40 mL), dried (MgSO4), filtered, concentrated in vacuo, filtered through a plug of silica and the solvent removed in vacuo to give the crude product as a colourless oil (381 mg). Purification by column chromatography (SiO2, hexane/Et2O 20:1) gave the title compound as a colourless oil (274 mg, 67% over 2 steps).
*Yield (%)  67
*Type of Yield Isolated product yield
Reference(s)  
AH Thesis_2011_pp58.pdf
AH Thesis_2011_pp145-167.pdf
Further information  Compound 78: 9-Vinylheptadeca-5,12-diyne

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Overall reaction? True
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Attached Files
CSRxnsScheme_78.cdx
AH Thesis_2011_pp58.pdf
AH Thesis_2011_pp145-167.pdf