Nucleophilic substitution at the anomeric position of 1,2-O-isopropylidenefuranose derivatives. A novel stereoselective synthesis of cyclic phosphates analogous to cAMP
作者:Miriam Romero、Luís Hernández、Leticia Quintero、Fernando Sartillo-Piscil
DOI:10.1016/j.carres.2006.10.015
日期:2006.12
.1,2-O-Isopropylidenefurano se derivatives were treated with various nucleophiles in the presence of either BF3 center dot OEt2 or trimethylsilyl trifluoromethanesulfonate (TMSOTO leading to substitution products in a regio- and stereoselective manner. In particular, nucleophilic substitution of 1,2-O-isopropylidenefuranose derivatives when treated with allyltrimethylsilane was controlled by steric and electronic factors (similar to Woerpel's stereoelectronic model). On the other hand, when 1,2-O-isopropylidenefuranose derivatives were treated with trimethylsilane, in the presence of bis-O-trimethylsityl-5-iodouracil or bis-O-trimethylsilyl-thymidine, substitution products were generated in high regio- and stereo selectivities via an unusual nucleophilic substitution with opening of the furanose ring. Based on these results, a stereoselective method for the synthesis of neutral cyclic phosphates analogous to cAMP was developed. (c) 2006 Elsevier Ltd. All rights reserved.