✍ Scribed by Gräf, Silke ;Braum, Manfred
No coin nor oath required. For personal study only.
(R)‐3‐Hydroxy‐4‐pentenoic acid (2), readily available by an aldol addition of doubly deprotonated (R)‐2‐hydroxy‐1,2,2‐triphenylethyl acetate (1) to acrolein, functions as a key intermediate for the synthesis of enantiomerically pure deoxy‐and aminodeoxyfuranosides 8–13. Iodolactonization of the acid 2 enables the generation of the second stereogenic center and provides the furanone skeleton of 6a which is submitted to reduction and various functional‐group manipulations. Whereas the halogen atom of 7a is easily replaced by lithium azide in an S~N~2‐type reaction to deliver 10a, a free‐radical substitution pathway is suitable for the conversion of 7b into the glycoside 8a. The latter compound serves as an intermediate in a formal synthesis of 3′‐azido‐2′,3′‐dideoxythymidine (AZT). On the other hand, the triflate 7c is converted into the diazide 12 by a twofold nucleophilic substitution. The novel aminodeoxy‐furanosides 11 and 13 are available in enantiomerically pure from upon catalytic hydrogenation of the azides 10 and 12.
📜 SIMILAR VOLUMES
## Abstract L‐Tryptophan methyl ester reacts with 1,1,3,3‐tetramethoxypropane to give methyl carbolinecarboxylate 2 as a 1:2 mixture of the (1__R__,3__S__) and (1__S__,3__S__) stereoisomers. Conversion to the corresponding amides (1__R__,3__S__)‐3 and (1__S__,3__S__)‐3 was accomplished by treatment