Stereocontrolled Preparation of Diversely Trifunctionalized Cyclobutanes

The expedient and stereoselective syntheses of small libraries of trifunctionalized cyclobutane scaffolds bearing an acid, an amine, and a third functional group are described. Starting from a single precursor, the readily available protected derivative of all-cis-2-amino-3-hydroxycyclobutane-1-carboxylic acid, cis-trans stereoisomers are obtained following an SN2-type reaction, while all-trans stereoisomers are obtained using the same strategy preceded by a C1 epimerization reaction.本文报道了带有羧基、氨基与第三种官能团的三官能化环丁烷骨架小型文库的便捷且立体选择性合成方法。以易得的全顺式-2-氨基-3-羟基环丁烷-1-羧酸的保护衍生物作为单一前驱体，通过SN2型反应可获得顺反立体异构体；而先经C1位差向异构化反应、再采用相同合成策略，则可得到全反式立体异构体。