Remarkable rate acceleration of water-promoted nucleophilic substitution of Baylis-Hillman acetate:: a facile and highly efficient synthesis of N-substituted imidazole

Without additional reagents, the Baylis-Hillman acetates 2 underwent nucleophilic Substitution reaction with imidazole readily in aqueous THF solution to afford the corresponding N-substituted imidazole derivatives 3 in good to excellent yields. Moreover, the reaction between the in situ generated DABCO salt of Baylis-Hillinan acetates 4 and imidazole occurs in aqueous THF providing the S(N)2 type products 5. The simpler operational procedure, better stereoselectivity and higher efficiency over conventional method make the present protocol practical for the preparation of imidazole derivatives. (c) 2005 Elsevier Ltd. All rights reserved.