Asymmetric Transfer Hydrogenation of <i>rac</i>-α-(Purin-9-yl)cyclopentones via Dynamic Kinetic Resolution for the Construction of Carbocyclic Nucleosides
An asymmetrictransfer hydrogenation viadynamickineticresolution of a broad range of rac-α-(purin-9-yl)cyclopentones was first developed. A series of cis-β-(purin-9-yl)cyclopentanols were obtained with up to 97% yield, >20/1 dr, and >99% ee. This also provides an efficient synthetic route to a variety of chiral carbocyclic nucleosides.
An efficient and facile three-component Mannich-type reaction on purine rings was described. This reaction proceeded smoothly under the catalysis of ethylenediamine at ambient temperature in high regioselectivities with exclusive N9-alkylated products. A wide range of purine derivatives were obtained in high yields.
Purines. I. The Chlorination of Certain Purinones with Phosphorous Oxychloride in the Presence of Aliphatic Tertiary Amines<sup>1</sup>