Combined directed ortho and remote metalation-Suzuki cross-coupling strategies. Efficient synthesis of heteroaryl-fused benzopyranones from biaryl O-carbamates.
A concise synthesis of heteroaryl dibenzopyranones 9a,b, 10a,b, 11a-c, and 12a-c has been achieved by the LDA-induced migration of heterobiaryl O-carbamates 18, 21, 25, and 30 which, in turn, were prepared in good yield using a combined directed ortho lithiation (DoM)-transition-metal-catalyzed Suzuki cross-coupling strategy. An efficient and general route to a wide variety of heterocycles including coumestans 19a,c and the previously unknown isothiocoumestan ring system 22b has been thereby achieved.
Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
Clint A
CA
James
Antonio Luiz
AL
Coelho
Matt
M
Gevaert
Pat
P
Forgione
Victor
V
Snieckus
D001578:Benzopyrans / Q000138:chemical synthesis*; D002219:Carbamates / Q000737:chemistry*; D003374:Coumarins / Q000138:chemical synthesis*; D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D008670:Metals / Q000737:chemistry; D055601:Organic Chemistry Phenomena
D001578:Benzopyrans; D002219:Carbamates; D003374:Coumarins; D006571:Heterocyclic Compounds; D008670:Metals; C505898:coumestan