Enantioselective Synthesis and Conformational Study of Cyclohexene Carbocyclic Nucleosides
摘要:
Enantioselective synthesis of a new family of unsaturated six-membered carbocyclic nucleosides using (R)-(-)-can one as starting material is described. Introduction of the base moiety via Mitsunobu reaction proceeded regio- and stereoselectively and with good chemical yield, while the Pd-coupling approach failed. H-1 NMR study and molecular modeling show the adenine compound exists in an equilibrium of H-3(2) and H-2(3) conformers (ratio 7:3) in favor of the 3'-endo half-chair conformation, with the base oriented in a pseudoaxial position. This conformational preference can be explained by the pi --> sigma*(C1')-(N1) interaction involving the antibonding orbital of the C1'-N bond.
Enantioselective Synthesis and Conformational Study of Cyclohexene Carbocyclic Nucleosides
摘要:
Enantioselective synthesis of a new family of unsaturated six-membered carbocyclic nucleosides using (R)-(-)-can one as starting material is described. Introduction of the base moiety via Mitsunobu reaction proceeded regio- and stereoselectively and with good chemical yield, while the Pd-coupling approach failed. H-1 NMR study and molecular modeling show the adenine compound exists in an equilibrium of H-3(2) and H-2(3) conformers (ratio 7:3) in favor of the 3'-endo half-chair conformation, with the base oriented in a pseudoaxial position. This conformational preference can be explained by the pi --> sigma*(C1')-(N1) interaction involving the antibonding orbital of the C1'-N bond.
CARBOCYCLIC NUCLEOSIDES AND PROCESS FOR OBTAINING SUCH
申请人:Stichting REGA V.Z.W.
公开号:EP1210347B1
公开(公告)日:2004-06-23
Enantioselective Synthesis and Conformational Analysis of Cyclohexene Carbocyclic Nucleosides
作者:Jing Wang、Piet Herdewijn
DOI:10.1080/15257779908041505
日期:1999.4
An enantioselective approach towards the synthesis of optically pure cyclohexene nucleosides 3 has been developed starting from (R)-carvone. The key steps are the regio- and stereoselective hydroboration of an exo double bond, the selective reduction of an enone intermediate and introduction of a base moiety by Mitsunobu reaction. Conformational analysis showed that the adenine base adopts predominantly in a pseudo-axial position.