Ralph N Salvatore

Mild and efficient synthesis of thiocarbonates and thiocarbamates via a three-component coupling utilizing Cs2CO3 and TBAI

Abstract The presence of cesium carbonate and tetrabutylammonium iodide (TBAI) facilitated efficient thiocarbonylation of alcohols, and thiocarbamation of amines, using carbon disulfide with alkyl halides. This protocol was mild, chemoselective, and efficient, compared to the existing methods.

Efficient Cs2CO3-promoted solution and solid phase synthesis of carbonates and carbamates in the presence of TBAI

Abstract Novel solution and solid-phase methods for the synthesis of carbonates and carbamates were developed using cesium bases and TBAI via a three-component coupling. Cesium carbonate not only promoted successful carbonylations of alcohols and carbamations of amines, but also suppressed common side reactions traditionally seen using existing protocols. Various alcohols and amines were examined, using a wide array of alkyl halides, and the results demonstrated this methodology was highly chemoselective. In particular, use of either sterically demanding substrates or amino acid derivatives afforded the corresponding products exclusively, offering a wide variety of applications such as novel protecting groups and peptidomimetic syntheses.

An efficient one-pot synthesis of N-alkyl carbamates from primary amines using Cs2CO3

Abstract A facile one-pot synthesis of N-alkyl carbamates is described. A primary amine, CO2, and an alkyl halide underwent a three-component coupling using cesium carbonate and tetrabutylammonium iodide (TBAI) giving rise to the resultant carbamate. In the presence of Cs2CO3, subsequent N-alkylation of the in situ generated carbamate with a different alkyl halide afforded various aliphatic N-alkyl carbamates, respectively.

Efficient synthesis of β-amino bromides

Abstract β-Aminoalcohols were smoothly converted to β-amino bromides using thionyl bromide and DMF, which were easily isolated without any further purification. Participation by the β-amino group in brominations not only enhanced reaction rates but also promoted stereo- and regioselectivities.

CsOH-promoted chemoselective mono-N-alkylation of diamines and polyamines

Abstract Selective N -alkylation of diamines and polyamines was carried out using cesium hydroxide, 4 A molecular sieves, and DMF. This protocol was highly chemoselective, favoring mono- N -alkylation over overalkylations.

Efficient and selective N-alkylation of carbamates in the presence of Cs2CO3 and TBAI

Abstract Mild and selective N -alkylation of carbamates was carried out in the presence of cesium carbonate, tetrabutylammonium iodide (TBAI), and a halide. This protocol was highly selective and efficient, offering aliphatic and aromatic N -alkyl carbamates exclusively in high yields.

Selective mono protection of diols, diamines, and amino alcohols using cesium bases

Efficient synthetic methods were developed for the synthesis of mono xanthates, as well as mono dithiocarbamates of diamines and amino alcohols. This protocol utilizes the three component coupling of diols, diamines, and amino alcohols using alkyl bromides and carbon disulfide in the presence of a cesium base and tetrabutylammonium iodide (TBAI).