2886-59-1Relevant articles and documents
Synthesis of 3-Methoxyphthalic Anhydride
Newman, Melvin S.,Kanakarajan, Kuppusamy
, p. 3523 - 3524 (1980)
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Rhodium(I)-Catalyzed Enantioselective C(sp3)—H Functionalization via Carbene-Induced Asymmetric Intermolecular C—H Insertion?
Liu, Bo,Xu, Ming-Hua
supporting information, p. 1911 - 1915 (2021/05/31)
Transition-metal-catalyzed C—H insertion of metal-carbene represents an excellent and powerful approach for C—H functionalization. However, despite remarkable advances in metal-carbene chemistry, transition metal catalysts that are capable of enantioselective intermolecular carbene C—H insertion are mainly constrained to dirhodium(II) and iridium(III)-based complexes. Herein, we disclose a new version of asymmetric carbene C—H insertion reaction with rhodium(I) catalyst. A highly enantioselective rhodium(I) complex-catalyzed C(sp3)—H functionalization of 1,4-cyclohexadienes with α-aryl-α-diazoacetates was successfully developed. By using chiral bicyclo[2.2.2]-octadiene as ligand, rhodium(I)-carbene-induced asymmetric intermolecular C—H insertion proceeds smoothly at room temperature, allowing access to a diverse variety of α-aryl-α-cyclohexadienyl acetates and gem-diaryl-containing acetates in good yields with good to excellent enantioselectivities (up to 99% ee). Furthermore, the synthetic utility of the reaction was highlighted by facile synthesis of a novel cannabinoid CB1 receptor ligand. This method may offer a new opportunity for the development of therapeutically exploitable cannabinoid receptor type ligands in medicinal chemistry.
Temporary thio-derivatization in the synthesis of (+)-4-acetylbromoxone
O'Byrne, Aisling,O'Reilly, Steven,Tighe, Catherine,Evans, Paul,Ciuffini, Laura,Gabriella Santoro
, p. 5936 - 5938 (2013/01/13)
A stereocontrolled synthesis of the marine natural products (+)-bromoxone (1) and (+)-4-acetylbromoxone (2) is reported. The sequence features the enzymatic kinetic resolution of 4-hydroxycyclohexenone (6) via its S-benzyl adduct. Thereafter, a base-mediated elimination-silylation generated an optically active (-)-4S-4-tert-butyldimethylsilyoxycyclohexenone (5), which then underwent diastereoselective epoxidation. Saegusa-Ito oxidation enabled formation of the corresponding α,β-unsaturated ketone 13. Bromination-elimination and subsequent removal of the silicon protecting group afforded (+)-bromoxone (1) which was converted into (+)-(4S,5R,6R)-4-acetoxy-2- bromo-5,6-epoxycyclohex-2-enone (2) [(+)-4-acetylbromoxone]. Using a luciferase gene reporter assay ED50 for NFκB inhibition of 9 μM was determined.
