Synthesis of the tetronate-containing core structure of the antibiotic abyssomicin C
The core structure of abyssomicin C (1) containing an oxabicyclooctanone ring and a tetronate was prepared from the addition product of lithium ethyl propiolate and 4-tert-butyldimethylsilyloxycyclohexanone. Tetronate formation via addition of sodium methanolate followed by hydrolysis gave the hydroxy tetronic acid 27. The spiro compound 27 could be cyclized to the tricyclic tetronate 23 by a transannular Mitsunobu lactonization. Alternatively, 27 could be prepared from the cyanohydrin cis-19.
Rath, Jean-Philippe,Eipert, Martin,Kinast, Stephan,Maier, Martin E.
p. 314 - 318
(2007/10/03)
Hydroxynitrile lyase-catalyzed addition of HCN to 4-substituted cyclohexanones: Stereoselective preparation of tetronic acids
The addition of HCN to 4-alkylcyclohexanones 1 to give cyanohydrins 2 is strongly catalyzed by hydroxynitrile lyases (HNLs). With PaHNL, from bitter almond, trans-addition occurs almost exclusively, yielding trans-2. With MeHNL, from cassava, cis-addition