Propargyl azides preparation

The preparation of the allene bis-epoxide 1 started with isovaleraldehyde 9. Addition of the protected propargyl alcohol 10 under the Carreira conditions led to 11 in > 95% . Mesylation followed by displacement with methyl cuprate provided the allene without loss of enantiomeric excess. Oxidation of the allene 12 with dimethyldioxirane could have led to any of the four diastereomers of the spiro bis epoxide. In the event, only two diastereomers were observed, as a 3 1 mixture. That 1 was the major diastereomer followed from its conversion to 3. The configuration of the minor diastereromer was not noted. Exposure of 1 to nucleophilic azide then gave the easily-purified 2. 

A-allylic amines are conveniently prepared in high yields by the reaction of azides with allylindium reagents in the presence of sodium iodide at ambient temperature (Equation (74)).307 Stannylation with tributylchloro-stannane occurs exclusively at the a-carbon, yielding allyltributylstannanes (E, Z)-isomerization of the allylic double bond depends largely upon the substitution pattern on the allylic moiety (Equation (75)).26 Allyl and propargyl bromides react with diphenyl diselenides in aqueous media to give allyl and propargyl selenides (Equation (76)).308 309... 

The same reaction was performed by using polystyrene-supported hydroxyproline 37.2 yhe solid catalyst 41 was prepared according to the procedure depicted in Scheme 3.12 by 1,3-dipolar cycloaddition of the azide-substituted Merrifield resin 40 with the O-propargyl hydroxyproline 38, which in turn was synthesized by a well-established method. 

The synthesis of cyclodextrin-like triazoles and macrocyclic carbohydrate/amino acid hybrids has been reported by Bodine et al. [66,67] and Billing et al. [68], respectively, through a common strategy based in the convergent cyclization of bifunctional azide/alkyne carbohydrate derivatives. Thus, Bodine et al. [66,67] prepared 2,3,6-tri-O-benzyl propargyl-a-D-mannopyranosyl... 

The preparation of low molecular weight cyclic PEI has been reported by Cortez and Grayson. At first, PAOx is prepared with both an allg ne at the a-terminus (initiation by propargyl tosylate) and an azide at the -terminus... 

Scheme 30.27 Preparation of macrocyclic PNIPAM by RAFT polymerization of Nl-PAM from an azide-functional chain transfer agent followed by transformation of the polymer chain end with propargyl acrylate...

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