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.
James
Clint A
CA
Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
Coelho
Antonio Luiz
AL
Gevaert
Matt
M
Forgione
Pat
P
Snieckus
Victor
V
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