A synthesis of [2.2.1]bicyclo nucleosides which is shorter and provides higher overall yields proceeds via the key intermediate of the general formula III, wherein R4 and R5 are, for instance, sulfonates and R7 is, for instance, a halogen or an acetate. From compounds of the general formula II, such as 3-O-aryl-4-C-hydroxymethyl-1,2-O-isopropylidene-&agr;-D-ribofuranose, intermediates of the general formula III are suitable for coupling with silylated nucleobases. Upon one-pot base-induced ring-closure and desulfonation of the formed [2.2.1]bicyclo nucleoside, a short route to each the LNA (Locked Nucleic Acid) derivatives of adenosine, cytosine, uridine, thymidine and guanidine is demonstrated. The use of the 5′-sulfonated ring-closed intermediate also allows for synthesis of 5′-amino- and thio-LNAs
                            一种合成[2.2.1]双环核苷的方法,该方法更短且提供更高的总收率,通过通式III的关键中间体进行,其中R4和R5例如是
磺酸盐,R7例如是卤素或
乙酸。从通式II的化合物,例如3-O-芳基-4-C-羟甲基-1,2-O-异丙基亚-
D-核糖,通式III的中间体适合与
硅化核碱基偶联。通过一锅法碱诱导的环闭合和去
磺酸化形成[2.2.1]双环核苷后,演示了
腺嘌呤、
胞嘧啶、尿
嘧啶、胸腺
嘧啶和
鸟嘌呤的LNA(锁定核酸)衍
生物的短路线。使用5'-
磺酸化的环闭合中间体还允许合成5'-
氨基和
硫代LNAs。