Site-selective and stereoselective transformations on p-quinols & p-quinamines

Abstract

The intermolecular transformation of simple substrates into highly functionalized scaffolds with multiple stereogenic centers is an attractive strategy in modern organic synthesis. Prochiral 2,5-cyclohexadienones, being stable and easily accessible, are...

Synthesis of Benzofuro[3,2-b]indol-3-one Derivatives via Dearomative (3 + 2) Cycloaddition of 2-Nitrobenzofurans and para-Quinamines

“…These precedents have demonstrated the great potential of heteroatomic nucleophile-driven dearomative cyclization reaction of 2-nitrobenzofurans in the construction of complex polyheterocyclic compounds. On the other hand, much attention has been paid to the application of para -quinamines as three-atom building blocks for the cascade reaction to construct nitrogen-containing heterocycles with structural diversity [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. Para -quinamines are often used as N -nucleophiles to undergo (3 + 2) cycloaddition with two-atom reaction partners, thus leading to the formation of hydroindoline-5-one scaffolds [ 49 , 50 , 51 , 52 , 53 ].…”

A Domino Dearomative ipso-Annulation/Desymmetrization Approach: Stereoselective Access to Tricyclic Alkaloid Skeletons

“…The rapid assembly of a complex structural framework containing tertiary and/or quaternary carbon centers from readily accessible precursors has garnered wide attention in current organic synthesis. , In this direction, domino reactions are attractive, playing a key role in the construction of multiple bonds in a single step under a similar reaction environment, and numerous competent strategies have been developed. − Among these, the combination of dearomatization with an intramolecular desymmetrization reaction could lead to complex structural motifs having quaternary carbon centers . Recently, domino functionalization/ ipso -annulation of readily available unsaturated amides and ketones has received substantial attention due to the capability to give diversely functionalized spirocyclic symmetrical dienones.…”

Desymmetrization of Cyclohexadienones through Phase-Transfer-Catalyzed Stereoselective Intramolecular Aza-Michael Addition with Chiral Sulfinamide Nucleophiles

“…In continuation of our research interests in catalytic methodologies for the asymmetric synthesis of heterocyclic compounds, 7 herein we conducted a phase-transfer catalysis (PTC) 8 -enabled stereoselective aza-Michael addition involving the use of a tethered chiral sulfinamide nucleophile for the desymmetrization of cyclohexadienones (Scheme 1c). 9 The PTC that incorporates quaternary ammonium salts (R 4 N + X − ) and CsF avoids the use of a strong base and enhances the stereoselectivity manifolds in the aza-Michael reactions. Through the PTC strategy, the desymmetrization reactions yielded various nitrogen-containing bicyclic compounds, 10 such as the core structures of a drug candidate for cancer treatment, 11 with high stereocontrol.…”