SYNTHESIS OF NEW 2',3'-MODIFIED URIDINE DERIVATIVES FROM 2',3'-ENE-2'-PHENYLSELENONYL URIDINE BY MICHAEL ADDITION-REACTIONS

The synthetic utilities of 2',3'-ene-2'-phenylselenones 12 and 13 as synthetic equivalent of a dication [CH2+ - CH2+] 5 have been demonstrated. They act as Michael acceptors, and undergo conjugate addition reactions at C-3' with various sulfur, nitrogen, oxygen and carbon nucleophiles giving various C-3' substituted-2,2'-O-anhydro-, or 2',3'-ene-3'-substituted, or 2',3'-fused nucleoside derivatives. Easy access to these 3'-substituted nucleosides from 2',3'-ene-2'-phenylselenones 12 and 13 make them powerful complement to the corresponding 2'-substituted derivatives obtainable from 2',3'-ene-3'-phenylselenonyl nucleoside 4 (ref. 72-74).