Synthesis of new A-conjugated Quinolone and Spiroindole Dammaranes by the Ozonolysis of 2,3-Indolodipterocarpol

An one-step and efficient access to the new dammarane A-quinolones by ozonolysis of 2,3-indolodipterocarpol at 0°C through the 1,3-dipolar cycloaddition of ozone to the C2-C3 double bond of the tri...