Preparation of macrocyclic lactones by ring closure of cesium carboxylates

Production of new polyene antibiotics by Streptomyces cellulosae after addition of ethyl(Z)-16-phenylhexadec-9-enoate.

“…Wetherefore designate compoundll as isochainin. The other newpolyenes are close relatives: 14-Hydroxyisochainin (12), r-hydroxyisochainin (13), and r,14-dihydroxyisochainin (14). All compounds showed antifungal activity roughly comparable to that of amphotericin B in preliminary tests.…”

Total Synthesis of Leucascandrolide A: A New Application of the Mukaiyama Aldol−Prins Reaction

“…5 (3) The in situ formation of nucleophilic cesium carboxylates from cesium carbonate and their subsequent displacement reactions are well precedented. 33 We anticipated that the addition of cesium carbonate to side chain acid 34, 18-crown-6, and macrocyclic bromide 8 would generate leucascandrolide A in a single step. Unfortunately, elimination product 36 and an olefin isomer of leucascandrolide A (35) were formed in a 1:1 mixture (eq 4).…”

An efficient and convenient transformation of α-haloketones to α-hydroxyketones using cesium formate

“…Cesium bases have demonstrated several merits in organic synthetic reactions [28][29][30][31][32][33][34], highlighted by comparative high solubilities [35], appropriate basicities and good stabilities [36][37][38][39][40][41]. In this work, we reported a safe and convenient method for the preparation of a-hydroxyketones from a-haloketones by using cesium formate (HCO 2 Cs).…”