- A stereocontrolled total synthesis of C-nucleosides
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A stereocontrolled, general synthesis of chiral C-nucleosides has been achieved through a common lactonic C- beta -glycoside intermediate which is readily obtainable from non-carbohydrate materials. The optically pure lactone having the natural D configuration is obtained through optical resolution of the seco acid by the Pirkle's method followed by relactonization. alpha -Aminomethylenation of the lactone with t-C//4H//9OCH left bracket N(CH//3 )//2 right bracket //2 yields 2-(2,3-0-isopropylidene- beta -D-ribofuranosyl)-2-(dimethylaminomethylene)acetic acid lactone, which undergoes base-assisted condensation with urea followed by deprotection to furnish naturally occurring pseudouridine. Analogously, construction of heterocycles using thiourea and guanidine converts the aminomethylene lactone to unnatural pyrimidine C-nucelosides, 2-thiopseudouridine and pseudoisocytidine, respectively.
- Sato,Hayakawa,Noyori
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p. 2515 - 2525
(2007/10/02)
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