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Activation of Glycosyl Phosphites under Neutral Conditions in Solutions of Metal Perchlorates in Organic Solvents
Author(s) -
Schene Heidrun,
Waldmann Herbert
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199806)1998:6<1227::aid-ejoc1227>3.0.co;2-4
Subject(s) - chemistry , glycosyl , anomer , glycoside , yield (engineering) , ether , organic chemistry , metal , medicinal chemistry , metallurgy , materials science
Glycosyl phosphites 1 – 3 derived from glucose are activated under neutral conditions and without the addition of any further promoter in 1 M solutions of LiClO 4 , Mg(ClO 4 ) 2 or Ba(ClO 4 ) 2 in ether, CH 2 Cl 2 , or CH 3 CN and react under these conditions with the alcohols 5 – 9 to give the glycosides 10 – 14 . The best results are obtained in the presence of Ba(ClO 4 ) 2 . In CH 2 Cl 2 and ether the α‐anomers predominate, in CH 3 CN the β‐isomers are formed in excess. Whereas the methyl phosphite 1 and the benzyl phosphite 3 deliver the desired glycosides in yields of 35‐66%, the ethyl phosphite 2 is a more reactive glycosyl donor, giving the glycosides 10 , 11 and 13 in 62‐95% yield.