A waste-minimized protocol for the preparation of 1,2-azido alcohols and 1,2-amino alcohols
作者:Eleonora Ballerini、Paolo Crotti、Ileana Frau、Daniela Lanari、Ferdinando Pizzo、Luigi Vaccaro
DOI:10.1039/c3gc40988k
日期:——
Under solvent-free conditions the reaction of epoxides 1a–i with trimethylsilylazide (2) catalyzed by polystiryl-supported fluoride (PS-DABCOF2) has led to the efficient preparation of the corresponding O-TMS protected 1,2-azido alcohols 3a–i that, by treatment with Dowex-H, gave the related 1,2-azido alcohols 4a–i in excellent yields (83–99% and 82–96%, respectively). The use of a flow procedure has allowed us to significantly minimize waste in the preparation of representative 1,2-azido alcohols 4a, 4c and 4i that have been obtained with E-factors of 1.6, 2.1, and 1.9, respectively. The 1,2-amino alcohols 5a, 5c and 5f have been also prepared, in quantitative yields, by reduction of the corresponding O-TMS protected 1,2-azido alcohols 3a, 3c, and 3f by Pd on the Al2O3/HCOOH system.
在无溶剂条件下,环氧化物1a–i与三甲基硅基叠氮化物(2)在聚苯乙烯支持的氟化物(PS-DABCOF2)催化下的反应有效地制备了相应的O-TMS保护的1,2-叠氮醇3a–i,通过处理Dowex-H得到了相关的1,2-叠氮醇4a–i,产率极佳(分别为83–99%和82–96%)。采用流动程序使我们显著减少了在制备代表性的1,2-叠氮醇4a、4c和4i过程中的废物,E因子分别为1.6、2.1和1.9。这些1,2-氨醇5a、5c和5f也通过把对应的O-TMS保护的1,2-叠氮醇3a、3c和3f在Pd/Al2O3/HCOOH体系下还原,获得了定量产率。