This review provides a broad perspective of the uses of amino acid fluorides in the synthesis of peptides and a wide range of other molecules including peptidomimetics, heterocycles and biologically active molecules.

A protocol employing FeCl3 in the presence of glacial AcOH is described for the less nucleophilic aniline and its variants, bromoacetic acid and sterically hindered amino acids.

a b s t r a c tA simple, mild, and an alternative protocol for the preparation of N,N 0 -disubstituted ureas from readily available ethers and cyanamides as starting materials is described. The protocol explores the reactivity of ether in a Ritter type reaction with cyanamide in the presence of BF 3 ÁEt 2 O and resulting in the formation of N,N 0 -disubstituted urea. Divinyl ether as well as MTBE (methyl tert-butyl ether) can be employed as ether components to afford allyl and tert-butyl ureas respectively.

Synthesis of chiralA convenient approach has been presented for the synthesis of N β -protected amino diselenides from the corresponding amino alkyl iodides using in situ generated NaBH 2 Se 3 as an efficient selenating reagent. All the diselenides are obtained in good yields under very mild conditions, short duration of time and the 10 protocol is free from racemization. The methodology has been effectively extended to the synthesis of Nprotected L-selenocystine methyl ester. Clean oxidation of N β -protected amino diselenides to the N β -protected amino seleninic acids using 35% aqueous H 2 O 2 has also been accomplished. The present protocol is compatible with all the common urethane protecting groups.

A simple and efficient method for the synthesis of N,N'-orthogonally protected imide tethered peptidomimetics is presented. The imide peptidomimetics were synthesized by coupling the in situ generated selenocarboxylate of N(α)-protected amino acids with N(α)-protected amino acid azides in good yields. The protocol was also successfully applied for the synthesis of hybrid tripeptidomimetics bearing both amide and imide functionalities. In addition, coumarinic imide conjugates of amino acids have been accomplished by employing this protocol. The present method provides a convenient and easy access to imide tethered peptidomimetics and is compatible with common protecting groups employed in peptide chemistry.

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a b s t r a c tA simple and efficient protocol for the synthesis of selenazole containing dipeptidomimetics using N a -amino selenocarboxamides and a-bromomethyl ketones is described. All the compounds made were isolated in good yields and fully characterized.

An unprecedented approach for the assembly of thioureido peptidomimetics is developed employing alkyl azides and dithiocarbamates. Dithiocarbamates react with alkyl azides with the liberation of N2 and elemental sulfur thereby leading to thiourea in a traceless manner. Thioureido peptidomimetics are thus furnished in good yields with no epimerization. This process is mild, free from the use of a base, scalable and step economic. The practicability of this methodology has been highlighted by the synthesis of N,N'-orthogonally protected thioureido peptidomimetics.