Sulfuric Acid → t-Butyl 1-bromocyclopentanecarboxylate

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Reaction Steps

To a mixture of 1-bromocyclopentanecarboxylic acid (36.99g) and anhydrous ether (35ml) in a 500ml pressure bottle, containing a magnetic stirrer-bar, was added concentrated sulphuric acid (3.5ml), followed by precondensed isobutene (150ml). 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°/0.5-2.0mm) (33.6g, 70%); λmax (CHBr3) 1702cm-1 ; τ (CDCl3) 7.78, 8.20 (cyclopentane protons) and 8.54 (C(CH3)3).

Provenance & Evidence