Optically Pure Haloselenuranes. First Synthesis and Nucleophilic Substitutions
摘要:
The first synthesis of optically pure haloselenuranes 1 has been accomplished by utilizing the 2-exehydroxy-10-bornyl group as a chiral ligand. Complete retention of the configuration has been observed in interconversion reactions between haloselenuranes 1 and selenoxide 2 and in nucleophilic substitution reactions of 1.
Nucleophilic substitutionreaction of (RSe)-chloroselenurane 1 with activemethylenecompounds proceeded in highly stereoselective manner with retention of configuration to give (SSe)-selenonium ylides 2. (SSe)- and (RSe)-Ylides, 2 and 3, were stereospecifically formed from the reaction of (RSe)- and (SSe)-selenoxides, 4 and 5, with activemethylenecompounds.