ChemInform Abstract: THE PREPARATION OF AMINO SUGARS AND BRANCHED-CHAIN SUGARS BY PALLADIUM-CATALYZED ALLYLIC SUBSTITUTION OF ALKYL HEX-2-ENOPYRANOSIDES

1981 ◽  
Vol 12 (30) ◽  
Author(s):  
H. H. BAER ◽  
Z. S. HANNA
Keyword(s):  
Amino Sugars ◽  
Allylic Substitution ◽  
Palladium Catalyzed ◽  
Branched Chain

The preparation of amino sugars and branched-chain sugars by palladium-catalyzed, allylic substitution of alkyl hex-2-enopyranosides

1981 ◽  
Vol 59 (5) ◽  
pp. 889-906 ◽  
Author(s):  
Hans H. Baer ◽  
Zaher S. Hanna
Keyword(s):  
Mass Spectra ◽  
Nmr Spectra ◽  
Optical Rotation ◽  
New Products ◽  
Catalytic Amount ◽  
Amino Sugars ◽  
H Nmr ◽  
Palladium Catalyzed ◽  
Branched Chain ◽  
High Yields

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 or C-alkylated, respectively, in an allylic position. Some analogous experiments were performed using the β-D-erythro anomer (2) and the α-D-threo epimer (3) of 1. The constitutions and configurations of the new products were established by means of mass spectra, 13C- and 1H-nmr spectra, and optical rotation data. The reactions of 1 were 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-threo configuration. The reactions of 2 appeared slightly less selective although they, too, furnished mainly 4-substituted 2-enopyranosides with retention of configuration. Regioselectivity was low or lacking in two C-alkylations performed with 3, which gave mixtures of 4-substituted 2-enosides and 2-substituted 3-enosides. Some aspects of conformation and optical rotation in enopyranosides are discussed.

Palladium-Catalyzed Asymmetric Allylic Substitution Using Phosphoramidite Ligands Bearing 1,1-Binaphthyl Skeleton

2008 ◽  
Vol 5 (5) ◽  
pp. 346-348 ◽  
Author(s):  
Yongguang Gao ◽  
Xinsheng Li ◽  
Weiyi Chen ◽  
Dongcheng Xu
Keyword(s):  
Allylic Substitution ◽  
Palladium Catalyzed

Origins of Enantioselectivity with Nitrogen−Sulfur Chelate Ligands in Palladium-Catalyzed Allylic Substitution

1999 ◽  
Vol 64 (22) ◽  
pp. 8256-8262 ◽  
Author(s):  
Harry Adams ◽  
James C. Anderson ◽  
Rachel Cubbon ◽  
Daniel S. James ◽  
John P. Mathias
Keyword(s):  
Allylic Substitution ◽  
Chelate Ligands ◽  
Palladium Catalyzed

New chiral phosphinoimidazolidine ligand in palladium-catalyzed asymmetric allylic substitution

2002 ◽  
Vol 43 (41) ◽  
pp. 7409-7411 ◽  
Author(s):  
Myung-Jong Jin ◽  
Sang-Han Kim ◽  
Sang-Joon Lee ◽  
Young-Mok Kim
Keyword(s):  
Allylic Substitution ◽  
Palladium Catalyzed
Sign in / Sign up

Export Citation Format

Share Document