Zn(OTf)2-Catalyzed 1,6-Conjugate Addition of Benzoxazinones to p-Quinone Methides: Access to 3,3-Diaryl-2-(2-oxo-2H-1,4-benzoxazin-3-yl)propanoic Acid Esters

An effective method for the synthesis of 3,3-diaryl-2-(2-oxo-2H-1,4-benzoxazin-3-yl)propanoic acid esters is reported. A novel zinc triflate-catalyzed regioselective 1,6-conjugate addition of vinylogous carbamates to p-quinone methides for accessing the title compounds has been developed. This protocol furnished the hybrid compounds in good to excellent yields. The reaction is rapid and has a broad substrate scope.

Zinc triflate catalyzed 1,3-indolylation of cyclohexanones: tandem condensation, dehydrogenation and aromatization sequence

1,3-Bis(1-alkyl-1H-indol-3-yl)benzene derivatives have been synthesized through a Zn(OTf)2 catalyzed reaction between cyclohexanones and indoles.

A Facile, Efficient and Selective Deprotection of P - Methoxy Benzyl Ethers Using Zinc (II) Trifluoromethanesulfonate

: Deprotection is significant and conducted over mild reaction conditions, in order to restrict any more side reactions with sensitive functional groups as well as racemization or epimerization of stereo center because the protective groups are often cleaved at last stage in the synthesis. P - Methoxy benzyl (PMB) ether appears unique due to its easy introduction and removal than the other benzyl ether protecting groups. A facile, efficient and highly selective cleavage of P - methoxy benzyl ethers was reported by using 20 mole% Zinc (II) Trifluoromethanesulfonate at room temperature in acetonitrile solvent over 15-120 min. time period. To study the generality of this methodology, several PMB ethers were prepared from a variety of substrates having different protecting groups and subjected to deprotection of PMB ethers using Zn(OTf)2 in acetonitrile. In this methodology, zinc triflate cleaves only PMB ethers without affecting acid sensitivity, base sensitivity and also chiral epoxide groups.

Efficient Conversion of Tertiary Propargylamides into Imidazoles via Hydroamination–Cyclization

A method to convert tertiary N-propargylamides into 1,2,4-trisubstituted imidazoles using ammonium chloride and zinc triflate as the catalyst is reported. The method is convenient, practical and employs conventional heating. It is also applicable to N-propargyl lactams and tends to populate the so-called ‘lead-like’ chemistry space.