4-Bromobutanal

Show how you would use a protecting group to convert 4-bromobutan-l-ol to hept-5-yn-l-ol. 

Vomifoliol (25) and blumenol C (118) were major by-products. The key step in a new synthesis54 of theaspirone (119) involves the coupling of the organolithium reagent (120) derived from 4-bromobutan-2-ol with (116). 

Bromobutane was purchased from Fisher Scientific Company and was freshly distilled from phosphorus pentoxide (P2O5) (bp 100-104°C). 

The Grignard reagent (29) derived from the ethylene acetal of 4-bromobutan-2-one, previously reported as unavailable, has now been prepared in THF and undergoes cyclization in refluxing solvent. The reaction of myrcene with magnesium results in the complex myrcene-magnesium which, on treatment with acetyl chloride or acetic... 

The use of acetals as carbonyl-protecting groups is illustrated by the synthesis of 5-hydroxy-5-phenylpentanal from benzaldehyde and 4-bromobutanal ... 

One obvious way to form a new carbon-carbon bond between these two molecules is to treat benzaldehyde with the Grignard reagent from 4-bromobutanal. However, during preparation, a Grignard reagent formed from 4-bromobutanal reacts... 

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