N-allyloxycarbonyl

Zur Anwendung dieses Verfahrens zur N-Deallyloxycarbonylierung von N-Allyloxycarbonyl-Nukleo-siden in Gegenwart von Butylamin siehe Y. Hayakawa, H. Kato, M. Uchiyama. H. Kajino u. R. Noyori, J. Org. Chem. 51, 2400 (1986). 

N-Allyloxycarbonyl-aspartic acid a-tert-Butyl Ester 34... 

Glycosidation of D-glucosamine. N-Allyloxycarbonyl derivatives of amines are obtained by reaction with 1 and N(C2H5)3. This derivative (2) of triacetyl-D-glucosamine undergoes selective p-glycosidation by virtue of anchimeric assistance.1... 

Diallyl dicarbonate was used for the allyloxycarbonyl protection of amino compounds including amino acids, amino sugars and nucleosides. Except for the reaction with amino acids, the reagent does not require an additional base, and the only by-products, allyl alcohol and carbon dioxide are both volatile. For example, N-allyloxycarbonyl glucosamine was obtained analytically pure by simple evaporation of the reaction mixture. 

In the SAPPHO process, the N-tert-butyloxycarbonyl (N-t-BOC), the N-allyloxycarbonyl (N-ALLOC), and the N,N-diallyl can be used for the protection of the alpha amino function. The functional side chains can be protected by different classical orthogonal protecting groups. 

Then, we have investigated the cleavage of allylcarbamates (Table 2). The reaction was first conducted on primary amines in homogeneous medium. Under treatment with mol 2 % of Pd(0) catalyst and 2.2 eq. of nucleophile N-Allocbenzyl-amine 7 was quantitatively cleaved to recover the parent molecule within 10 minutes (entry 1). However, when N-allyloxycarbonyl-N-methyl benzylamine 8 was allowed to react under the same conditions, the undesired reaction of N-allylation... 

The catalytic system can be recycled up to 10 times as presented in the following scheme (the procedure is applied on N-methyl N-allyloxycarbonyl benzylamine), without loss of efficiency. After completion of the reaction, the first schlenck tube containing the free amine in the organic layer and the catalyst in the aqueous layer is linked, by a siphon tube, to another schlenck tube containing the protected amine dissolved in butyronitrile. The aqueous layer with the active catalyst is transferred under argon pressure into the second tube, over the fresh solution of N-allyloxycarbonyl-N-methyl benzylamine. 

A SPOS approach to DNA synthesis was reported very recently. It involves a ten-step synthesis of a phosphoramidite building block of I -aminomethylthymidine starting from 2-deoxyribose [46]. Microwave-mediated deprotection of a corresponding N-allyloxycarbonyl (alloc-) protected nucleoside and acylation with the residue of pyrene-l-ylbutanolic acid (pyBA) were described (Scheme 16.25). Removal of the alloc protecting group was achieved on a support (controlled pore glass, cpg) under microwave conditions (80 °C, 10 min) to ensure full conversion. 

N-Allyloxycarbonyl functions can be efficiently removed by treatment with a palladium(O) catalyst [Pd (dba). CHCl,] and formic acid (3-4 equivalents) at 30 °C in THF. The method... 

Ni-carbonyl as allylophilic reagent added all at once to a mixture of -decyl allyl carbonate, TMEDA, and dry, argon-satd. dimethylformamide, the stirred mixture warmed slowly to 55°, and the product isolated after 4 hrs. 1-decanol. Y 95%. - Similarly in the presence of water N-Allyloxycarbonyl-dl-phenyl-alanine dl-phenylalanine. Y 83%. F. e. s. E. J. Corey and J.W. Suggs, J. Org. Chem. 38, 3223 (1973). 

Zero-valent metal complexes cannot be used directly for the synthesis of polypeptide hybrid block copolymers. However, N° -allyloxycarbonyl-amino acid allyl amides can be used as universal precursors for the amido-amidate nickelacycle initiators (Scheme 15.8). As shown in Scheme 15.8, the N°"-allyloxycarbonyl-amino acid derivatives may undergo tandem oxidative additions to nickel(O) giving the nickelacycle initiators. This method was initially employed for the synthesis of block copolypeptides and was then expanded by Deming and coworkers to a variety of hybrid structures. 

The combination of the N-terminal allyloxycarbonyl (Aloe) group (34) with the tert-butyl ester proved to be a particularly efficient tool in the synthesis of complex glycopeptides, as has been demonstrated in the synthesis of sensitive fucosyl chitobiose glycopeptides (19). The Aloe group was... 

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. 

Tables. a(l-3)Galactosylations with various non-natural N-acyl-glucosamides according Fig. 8 alloc=allyloxycarbonyl Z=benzyloxycarbonyl...

The preparation of the trisaccharide 11.40 was carried out by condensation of imidate 11.45 with acceptor 11.43 in the presence of TMSOTf to afford disaccharide 11.50 in 87% yield (Scheme 14). Conversion of 11.50 into glycosyl acceptor 11.51 was achieved by de-isopropylidination and acetylation followed by removal of the allyloxycarbonyl group. Glycosyl acceptor 11.51 was subsequently condensed with imidate 11.44 in the presence of BF3-Et20 to give the ttisaccharide derivative 11.52 in 81 % yield. The deprotection, oxidation, and N-acetylation sequence was achieved as described for 11.39 to afford 11.40 in 66% yield over fom steps. 

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