34016-03-0Relevant academic research and scientific papers
Strategies for the construction of morphinan alkaloid AB-rings: Regioselective Friedel-Crafts-type cyclisations of γ-aryl-β-benzoylamido acids with asymmetrically substituted γ-aryl rings
Davies, Stephen G.,Goddard, Euan C.,Roberts, Paul M.,Russell, Angela J.,Smith, Andrew D.,Thomson, James E.,Withey, Jonathan M.
, p. 274 - 284 (2016)
The regioselectivity of the Friedel-Crafts-type cyclisation of a range of γ-aryl-β-benzoylamido acids, bearing oxy substituents at the C(3)- and C(4)-positions of the γ-aryl ring, has been investigated. In all of the cases examined (with 3,4-dimethoxy, 3,4-methylenedioxy and 3-hydroxy-4-methoxy substituents) the Lewis acid promoted cyclisation proceeds with exclusive regioselectivity for attack at the C(6)-position rather than at the C(2)-position, and furnishes the corresponding N- and O-protected 3-amino-6,7-dihydroxy-1-tetralone derivatives. This inherent regioselectivity can be overturned by the regioselective introduction of chlorine as a blocking group for the C(6)-position; subsequent Lewis acid promoted cyclisation then proceeds with exclusive regioselectivity for attack at the C(2)-position to deliver the corresponding N- and O-protected 3-amino-5-chloro-7,8-dihydroxy-1-tetralone derivative. These complementary cyclisation protocols represent useful methods for the preparation of these benzo-fused carbocyclic ring systems, which are the functionalised AB-rings of a range of morphinan alkaloids.
Convergent Total Synthesis of Lamellarins and Their Congeners
Morikawa, Daiki,Morii, Kazuki,Yasuda, Yuto,Mori, Atsunori,Okano, Kentaro
, p. 8603 - 8617 (2020/07/16)
A convergent total synthesis of lamellarins S and Z is described. The synthesis features a halogen dance of an easily accessible α,β-dibromopyrrole promoted by an ester moiety. The resultant β,β′-dibromopyrrole undergoes a ligand-controlled Suzuki-Miyaura coupling to provide a range of diarylated pyrrole derivatives. The established synthetic method was also applicable to the synthesis of ningalin B and lukianols A and B.
