Stereochemistry of Nucleophilic Addition Reactions. VIII. Preparation of 1,5-Anhydro-4,6-<i>O</i>-benzylidene-2,3-dideoxy-3-nitro-D-<i>erytho</i>-hex-2-enitol and Its Reactions with Some Nucleophiles
作者:Tohru Sakakibara、Yutaka Nomura、Rokuro Sudoh
DOI:10.1246/bcsj.53.1642
日期:1980.6
having an axial and equatorial deuterium atom at C-2 in an approximate ratio of 2:1. On the other hand, the reaction with hydrogen cyanide gave predominantly the adduct with the manno configuration, together with small amounts of a cyano olefin. The reaction with hydrazoic acid yielded addition products with the gluco and manno configurations; the ratio was strongly affected by the solvent used.
Abstract Several nucleophiles were separately treated with methyl and phenyl 2,3-anhydro-4,6- O -benzylidene-3-deoxy-3-nitro-β- d -allopyranoside, to give 2-substituted aldos-3-ulose derivatives. In the latter case, the subsequent β-elimination of the aglyconic phenyl group always occurred to afford the corresponding glycal. Reaction mechanisms thereof are also discussed.
Reactivities of 2-<i>C</i>- and 3-<i>C</i>-Nitro-α- and β-D-<i>erythro</i>-Hex-2-enopyranoside Derivatives towards Methanol and AM1 Studies upon Their Stereoselectivities
The rates of the reactions of six nitro enosides with methanol-d4 in dimethyl sulfoxide-d6 were determined by 1H NMR spectroscopy. Their reactivities and stereoselectivities were discussed including the results of AM1 calculations of model compounds.
Preparation of methyl 4,6-O-benzylidene-2,3-dideoxy-2,3-dinitro-α-D-glucopyranoside and its selective conversion into the corresponding 2-nitro-2-enopyranoside
Abstract Treatment of methyl 4,6- O -benzylidene-2,3-dideoxy-3-nitro-α- D - erythro -hex-2-enopyranoside ( 3 ) with sodiumnitrite in benzene-water in the presence of small amounts of tributylhexadecylphosphonium bromide as a phase-transfer catalyst afforded the 2-nitro alkene 4 in 47% yield. A similar reaction in the presence of 1.3 equiv. of acetic acid gave the 2,3-dinitro derivative 5 in 58% yield;
Reactions of methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-α- and-β-d-erythro-hex-2-enopyranosides with phenylacetonitrile: Preparation and structural determination of adducts and an isoxazole derivative
作者:Tohru Sakakibara、Rokuro Sudoh
DOI:10.1016/0008-6215(83)84004-x
日期:1983.9
Treatment of methyl 4,6- O -benzylidene-2,3-dideoxy-3-nitro-α- d - erythro -hex-2-enopyranoside with phenylacetonitrile afforded adducts having the d - manno ( 2 and 3 ) and d - gluco configurations ( 4 and 5 ), the isoxazole 6 , the cyano alkene 7 , and the nitro alcohols 9 and 10 . Similar reaction of the β anomer 11 gave adducts having the d - gluco configuration ( 12 and 13 ) and the nitro alcohol