Enantioselective one-carbon expansion of aromatic rings by simultaneous formation and chromoselective irradiation of a transient coloured enolate

Abstract

Enantioenriched seven-membered carbocycles are structural motifs in many molecules of structural and biological interest. We report a simple, practical, transition metal-free and mechanistically unusual method for the enantioselective synthesis of...

C(sp3)-Arylation by Conformationally Accelerated Intramolecular Nucleophilic Aromatic Substitution (SNAr)

“…Amide tethers as conformational controllers 72 , 73 also hold promise for the assembly of benzylic stereocenters. 74 , 75 In addition, we are using the conformational preference of anilide congeners to develop other types of intramolecular transition metal-free couplings, including C-alkenylations. 76 − 79 …”

“…Looking ahead, with conformational preorganization firmly established as a means of accelerating simple electrophilic arylation, we are seeking to apply the approach to the asymmetric arylation of enantiotopic secondary C–H bonds, and the catalytic, enantioselective arylation of stabilized carbanions. Amide tethers as conformational controllers , also hold promise for the assembly of benzylic stereocenters. , In addition, we are using the conformational preference of anilide congeners to develop other types of intramolecular transition metal-free couplings, including C-alkenylations. − …”

The synthesis of seven- and eight-membered rings by radical strategies

“…Intriguingly, in 2022, Clayden's group reported the transposition of simple achiral benzamide to chiral cycloheptatriene initiated by the C-radical generated from visible light-induction, which was an uncommon radical process (Scheme 34). 63 Various aromatic structures tolerated the reaction conditions well; moreover, when R 2 was substituted by methyl, the desired product could be obtained in yield, indicating that the spatial site resistance had less influence on the system. Notably, the production of the enantioselective product is mainly because the chiral lithium amide is used, which enriches a variety of cycloheptatrienes.…”

Visible light-driven dearomative ring expansion of (aza)arenes to access dihydrofuran-based polycyclic compounds

“…[2][3][4][5][6][7] Nonetheless, the use of hazardous and unstable diazo compounds as reaction partners constitutes a frustrating dilemma, stimulating continuous exploration of alternative protocols. To this end, the Clayden group in 2003 devised a photochemical ring expansion for lithiated benzamides (Scheme 1B), 8 which recently demonstrated its robustness 9 by successfully preparing enantioenriched products through the pairing of chiral anions with lithium salts. Furthermore, Beeler and coworkers in 2021 described a photochemical rearrangement of aromatic N-ylides to furnish azepines (Scheme 1C).…”