Thioglycoluril as a Novel Organocatalyst: Rapid and Efficient α-Monobromination of 1,3-Dicarbonyl Compounds

Abstract

Thioglycoluril as a novel hydrogen-bonding organocatalyst, combined with NBS, in MeOH provided rapid and efficient α-monobromination of 1,3-dicarbonyl compounds in excellent yields at room temperature. A bifunctional catalytic mechanism was proposed from these results.

Key words

organocatalysis - thioglycoluril - hydrogen bond - α-mono­bromination - 1,3-dicarbonyl compounds

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21

Crystal Data for Compound 1d C₁₆H₁₄N₄S₂, M = 326.43, orthorhombic, a = 11.153 (3), b = 8.0271 (19), c = 8.5859 (19) Å, α = 90.00˚, β = 90.00˚, γ = 90.00˚, V = 768.6 (3) Å^³, T = 298 (2) K, space group Pmn2 (1), Z = 2, µ(Mo Kα) = 0.347 mm^-¹, 4575 reflections measured, 1417 unique (R _int = 0.0363) which were used in all calculations. The final wR ₂ (F ₂) was 0.1796 (all data). CCDC 708178 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Center, 12, Union Road, Cambridge CB2 1EZ, UK; fax: [phone]; email: [e-mail]].