Reaction #445425

Reaction equation

1-Propynylmagnesium bromide

ethyl bromide

propyne

methyl phenylglyoxylate

HCl

magnesium

→

Methyl α-Phenyl-α-(1-propynyl)glycolate

Solvents

THF

THF

Ether

Conditions

Workup

1. 1
   workup.ADDITIONpoured onto a slurry of ice and 25 ml
2. 2
   Otherthe layers were separated
3. 3
   Otherdried
4. 4
   workup.DISTILLATIONthe residue distilled
5. 5
   Otherto yield 13.1 g
6. 6
   Othermelted at 64°-65° after recrystallization from 20°-40° petroleum ether

Procedure

1-Propynylmagnesium bromide (0.2 mole) was made from magnesium (4.8 g., 0.2 g. atom) ethyl bromide (21.8 g., 0.2 mole) and excess propyne gas in 400 ml. of THF. The Grignard reagent then was siphoned under nitrogen into an addition funnel and added dropwise over a 40 minute period to a cooled solution of methyl phenylglyoxylate (32.8 g., 0.2 mole) in 200 ml. of THF. A slight temperature rise took place. The reaction mixture was stirred for 24 hours, and then poured onto a slurry of ice and 25 ml. conc. HCl. Ether was added, and the layers were separated. Several more ether extracts were made and the organic extracts combined and dried. The volatile components were stripped subsequently in vacuo and the residue distilled to yield 13.1 g. (32%) of the product, b.p. 109°-12° (0.2 mm.). The oil solidified on standing and melted at 64°-65° after recrystallization from 20°-40° petroleum ether.

Source