Unusual multiple insertion of diazo carbonyl compounds into (purin-6-yl)benzene derivative

The consecutive alkylation of 9-isopropyl-6-phenyl-9H-purine with methyl 2-diazo-3,3,3-trifluoropropionate and diethyl diazomalonate proceeds at the phenyl substituent firstly via ortho-C-H activation under chelation-assistance of the purine core, followed by classical electrophilic metal carbenoid insertion to the C-H bond of a malonate moiety.