Sulfuric Acid → t-Butyl 1-bromocyclopentanecarboxylate

Reaction equation

[Br:1][C:2]1([C:7]([OH:9])=[O:8])[CH2:6][CH2:5][CH2:4][CH2:3]1.S(=O)(=O)(O)O.[CH2:15]=[C:16]([CH3:18])[CH3:17]>CCOCC>[Br:1][C:2]1([C:7]([O:9][C:16]([CH3:18])([CH3:17])[CH3:15])=[O:8])[CH2:6][CH2:5][CH2:4][CH2:3]1

Participants

Procedure

To a mixture of 1-bromocyclopentanecarboxylic acid (36.99 g) and anhydrous ether (35 ml) in a 500 ml pressure bottle, containing a magnetic stirrer-bar, was added concentrated sulphuric acid (3.5 ml), followed by precondensed isobutene (150 ml). The bottle was sealed, and stirred at ambient temperature for 20 hours. The bottle was then opened excess isobutene was evaporated, and the residue in ether was washed with aqueous sodium bicarbonate solution and water, dried, and concentrated. The residue was distilled under reduced pressure to give the title ester (b.p. 66°-74°/0.5- 2.0 mm) (33.6 g, 70%); λmax (CHBr3) 1702 cm-1 ; τ (CDCl3) 7.78, 8.20 (cyclopentane protons) and 8.54 (C(CH3)3).