Protective groups allyloxycarbonyl

Other carbamates in which the O-alkyl bond can be easily cleaved can serve as amino-protecting groups. Allyloxycarbonyl groups are cleaved by a combination of tributyltin hydride and a Pd(II) catalyst." This reaction involves liberation of the carbamic acid by oxidative addition to the palladium. The allylpalladium species is then reductively cleaved by the stannane. 

H Kuntz, C Unverzagt. The allyloxycarbonyl (Aloe) moiety — conversion of an unsuitable into a valuable amino protecting group for peptide synthesis. Angew Chem Int Edn Engl 23, 436, 1984. 

T Vorherr, A Trzeciak, W Bannwart. Application of the allyloxycarbonyl protecting group for the indole of Trp in solid-phase peptide synthesis. Int J Pept Prot Res 48, 553, 1996. 

Selective removal of allyl and allyloxycarbonyl protecting groups promoted by Pd/tppts catalytic systems (Equation 14) 43 536 540 Hydrocyanation of 1,3-butadiene and 3-pentene nitrile to adiponitrile (Equation 15) catalysed by Ni/tppts systems in the presence of reducing agents, such as NaBfL, or ZnCb49 541-542... 

The syntheses of pyrimido[l,2-a]quinoline chromophore of pseudobactins are depicted in Schemes 6 and 7 (88MI4 90JOC4246). When allyloxycarbonyl and phthaloyl protective groups were used, then along with pyrimido[l,2-a]quinoline derivatives 410 and 411, tetracyclic 412, corresponding to the chromophore of azobactin, was formed (Scheme 6). Pyrimido[l,2- ]quinoline (413) was obtained in good yield when 2,2,2-... 

F.Guibf and Y. Saint M Leux, The allyloxycarbonyl group for alcohol protection Quantitative removal or transformation into allyl protecting group via w-allyl complexes of palladium, Tetrahedron Lett. 22 3391 (1981). 

The deblocking can be conducted in quantitavive yield, using trifluoroacetic acid at room temperature. Another protection group used in combination with EDC is the 3-(3-pyridyl)allyloxycarbonyl (Paloc) group. In this reaction DAEC is used in combination with N-hydroxybenzotriazole. 

The allyloxycarbonyl group [269] has shown a wide application in organic synthesis, especially in the fields of peptides, nucleotides, and carbohydrates. Allyloxycarbonyl derivatives are more easily prepared than the corresponding allyl ethers and they are more stable than ester protecting groups which find frequent use in carbohydrate chemistry. 

More recently Kunz and co-workers described a synthesis of 2,6-dideoxy-2,6-diaminopyra-noside libraries [73]. The scaffold 120 allows for selective deprotection of four positions in a manner that is independent of the sequence (O Scheme 11). Different functional groups have been incorporated at each position to give 121-4, which can then be cleaved from the solid support. For example, the 2-A-allyloxycarbonyl protecting group of 120 can be selec-... 

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