Synthesis and Reactions of Carbohydrate Trifluoro-Methanesulfonates (Carbohydrate Triplates)

Abstract

D e p a r t m e n t of C h e m i s t r y C l e v e l a n d S t a t e U n i v e r s i t y C l e v e l a n d , O h i o 44115 TABLE OF CONTENTS I . I n t r o d u c t i o n 11. R e l a t i v e R e a c t i v i t y of Several S u l f o n i c 111. S y n t h e s i s of C a r b o h y d r a t e T r i f l u o r o m e t h -E s t e r s a n e s u l f o n a t e s ( C a r b o h y d r a t e T r i f l a t e s ) 1V. Reactions of C a r b o h y d r a t e T r i f l a t e s A. S u b s t i t u t i o n Reactions 1. F a c t o r s E f f e c t i n g t h e N u c l e o p h i l e 2. I n f l u e n c e of t h e S o l v e n t B. 9 -A l k y l a t i o n Reactions 1. D i s a c c h a r i d e S y n t h e s i s 2 .D e r i v a t i v e F o r m a t i o n C . R e a r r a n g e m e

Synthesis and Stereocontrolled Equatorially Selective Glycosylation Reactions of a Pseudaminic Acid Donor: Importance of the Side-Chain Conformation and Regioselective Reduction of Azide Protecting Groups

“…Application of the Lattrell–Dax protocol − then gave the 8- epi -isomer 39 in 72% yield. It is noteworthy in this sequence that a secondary triflate is displaced in preference to a primary arenesulfonate ester, testifying to the power of the trifloxy group as a nucleofuge in substitution reactions . Subsequently, the triisopropylbenzenesulfonyl group was displaced with sodium iodide in hot acetone to give an 81% yield of 40 , which on hydrogenolysis over palladium on carbon in ethyl acetate and triethylamine afforded 91% of the 9-deoxy compound 41 .…”

Trifluoromethanesulfonate Anion as Nucleophile in Organic Chemistry

“…The trifluoromethanesulfonate anion (triflate, TfO – ) is an outstanding leaving group and is widely used as such in organic chemistry, , nowhere more so than in carbohydrate chemistry. − Conversely, the use of triflate as nucleophile in substitution reactions, albeit exploited since the very beginnings of triflate chemistry for the formation of simple alkyl triflates, − is rarely considered, even though triflate is widely recognized as a coordinating anion in inorganic chemistry . This Synopsis summarizes the literature on the action of triflate as nucleophile, whether by design or accident, with the aim of dispelling the notion of triflate as an innocent bystander in many reactions.…”

New Electronic Analogs of the Sialyl Cation: N-Functionalized 4-Acetamido-2,4-dihydroxypiperidines. Inhibition of Bacterial Sialidases

“…Desilylation of 12 afforded alcohol 13 , which was then converted to the triflate 14 . The hindered base 2,6-di- tert -butyl-4-methylpyridine had to be used in order to obtain the triflate in high yield . Triflate 14 was sufficiently stable to purify it by column chromatography on silica gel, but decomposed slowly at 4 °C, and so was used immediately after purification.…”