THE PREPARATION OF AMINO-SUGARS AND BRANCHED-CHAIN SUGARS BY PALLADIUM-CATALYZED, ALLYLIC SUBSTITUTION OF ALKYL HEX-2-ENOPYRANOSIDES
THE PREPARATION OF AMINO-SUGARS AND BRANCHED-CHAIN SUGARS BY PALLADIUM-CATALYZED, ALLYLIC SUBSTITUTION OF ALKYL HEX-2-ENOPYRANOSIDES
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DOI：
10.1139/v81-128
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
HANNA, ZS
中科院分区：
文献类型：
--
作者：
BAER, HH;HANNA, ZS
Ethyl 4,6-di-O-acetyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranoside (1) in the presence of triphenylphosphine and a catalytic amount of tetrakis(triphenylphosphine)palladium(0) reacted with a variety of amines or with reactive methylene compounds to give high yields of products aminated orC-alkylated, respectively, in an allylic position. Some analogous experiments were performed using the β-D-erythroanomer (2) and the α-D-threoepimer (3) of1. The constitutions and configurations of the new products were established by means of mass spectra,13C- and1H-nmr spectra, and optical rotation data. The reactions of1were found to be highly regio- and stereoselective, giving almost exclusively 4-substituted 2-enopyranosides with retention of configuration, except in the case of dibenzylamine which produced a mixture of the corresponding enoside and its 2-substituted, 3,4-unsaturated isomer having the α-D-threoconfiguration. The reactions of2appeared slightly less selective although they, too, furnished mainly 4-substituted 2-enopyranosides with retention of configuration. Regioselectivity was low or lacking in twoC-alkylations performed with3, which gave mixtures of 4-substituted 2-enosides and 2-substituted 3-enosides. Some aspects of conformation and optical rotation in enopyranosides are discussed.
