Highly diastereoselective approach toward (+/-)-tetraponerine T6 and analogues via the double cycloisomerization-reduction of bis-alkynylpyrimidines.

ABSTRACT: A new, short, and efficient approach toward tricyclic alkaloids, involving the double cycloisomerization-reduction of bis-alkynylpyrimidines 3a-m, has been developed. The requisite bis-alkynylpyrimidines 3a-m were readily prepared via regioselective sequential Sonogashira coupling reactions of dibromopyrimidines 1. Bis-alkynylpyrimidines 3a-m were converted into the 5-6-5 tricyclic heteroaromatic cores 4a-m via the Cu(I)-assisted double cycloisomerization reaction. The reaction proceeded stepwise, which was confirmed by the isolation of the mono-pyrrolization intermediate 5. The structure of 5 was assigned by 2D NMR and by independent synthesis. Cycloisomerization of 5 under standard conditions afforded tricyclic 4g in 89% yield. The PtO2-catalyzed hydrogenation of bis-pyrrolopyrimidines 4

SUBMITTER: Kim JT 

PROVIDER: S-EPMC3686648 | biostudies-literature | 2004 Aug

REPOSITORIES: biostudies-literature