STRUCTURE DETERMINATION AND SYNTHESIS OF A NEW GIBBERELLIN, GA(99), FROM SPINACH PLANTS - 2-BETA-HYDROXY-GA(19)

The structure of a new gibberellin, (GA(99), isolated from Spinach pla nts has been determined to be 2 beta-hydroxy-GA(19) (6) by synthesis f rom gibberel ic acid. The key steps in the preparation involved the re duction under Luche conditions of a Delta(1(10))-2-one derivative to f urnish the critical 2 beta-stereochemistry, intramolecular cyclopropan ation of the Delta(1(10)) bond by a 4 alpha-diazoacetyl group followed by Li-NH3 reduction, and then oxidative cleavage of the resulting cyc lopentanone by oxygenation of the derived potassium enolate.