All-carbon quaternary centers in natural products and medicinal chemistry: recent advances

Highly enantioselective [3+2] coupling of 3-substituted indoles with quinone monoimines promoted by a chiral phosphoric acid has been reported. A large variety of benzofuroindolines were prepared in moderate to good yields (up to 98%) with generally excellent enantioselectivities (up to 99 % ee).

Highly Enantioselective [3+2] Coupling of Indoles with Quinone Monoimines Promoted by a Chiral Phosphoric Acid

Disubstituted oxindoles represent an important family of bioactive compounds and synthetic derivatives that mimic natural products. The construction of the asymmetric quaternary carbon at C-3 or C-2 is therefore a challenging problem for organic chemists. In the last years, many papers have appeared on asymmetric catalytic methods for the synthesis of these compounds, in particular about spirocyclic derivatives and this literature has been largely reviewed, as well as the literature on 3-substituted-3-hydroxyoxindoles and 3-substituted-3-aminooxindoles. On the other hand, the literature on non-spirocyclic 3,3-dialkyloxindoles as well as on 2,2-disubstituted 3-indolinones has not fully reviewed since our previous review on this topic. This review aims to fill this gap covering the literature on these topics.

Abbreviations: Alloc=allyloxycarbonyl; Ant=anthracenyl; BINOL=1,1′-binaphthalene-2,2′-diol; Boc=t-butoxycarbonyl; Bz=benzoyl; Cbz=benzyloxycarbonyl; CSA=camphorsulfonic acid; Cy=cyclohexyl; DABCO=1,4-diazabicyclo[2.2.2]octane; dba=bis(dibenzylideneacetone); DBU=1,8-diazabicyclo[5.4.0]undec-7-ene; DDQ=2,3-dichloro-5,6-dicyano-1,4-benzoquinone; (DHQD)2AQN=hydroquinidine (anthraquinone-1,4-diyl) diether; (DHQD)2PHAL=hydroquinidine 1,4-phthalazinediyl diether; (DHQD)2PYR=hydroquinidine 2,5-diphenyl-4,6-pyrimidinediyl diether; DIPEA=N,N-diisopropylethylamine; esp=α,α,α′,α′-tetramethyl-1,3-benzenedipropionic acid; HFIP=1,1,1,3,3,3-hexafluoro-2-propanol; HMDS=hexamethyldisilazane; β-ICD=β-isocupreidine; LG=leaving group; Mes=2,4,6-trimethylphenyl; Moc=methoxycarbonyl; MOM=methoxymethyl; MS=molecular sieves; MsOH=methanesulfonic acid; NHC=N-heterocyclic carbene; Npt=naphthyl; PG=protecting group; Phg=phenylglycine; Phth=phthalimidyl; Piv=2,2-dimethylpropanoyl; PMB=4-methoxybenzyl; Red-Al=sodium bis(2-methoxyethoxy)aluminium hydride; Suc=succinimidyl; TBDPS=tert-butyldiphenylsilyl; TBS=tert-butyldimethylsilyl; TES=triethylsilyl; TIPS=triisopropylsilyl; TMEDA=N,N,N′,N′-tetramethylethylenediamine; TMG=1,1,3,3-tetramethylguanidine; TMS=trimethylsilyl; Ts=4-toluenesulfonyl.

Recent Catalytic Asymmetric Syntheses of 3,3-Disubstituted Indolin-2-ones and 2,2-Disubstituted Indolin-3-ones

Optically active α-arylation carbonyl units are widely present in a wide variety of drugs, bioactive natural products, and valuable pharmacologically active molecules. Catalytic enantioselective α-...

Catalytic Enantioselective α-Arylation of Carbonyl Enolates and Related Compounds

Asymmetric reactions and the synthesis of various quinones, carried out in the presence of chiral organocatalysts and metal–ligand complexes, are reviewed here. The role of quinones as Michael donors/acceptors, Diels–Alder dienophiles and 1,3-dipolarophiles has been extensively investigated to access complex structural frameworks. Additionally, reports in the literature on the stereoselective synthesis of simple and complex quinoidal compounds with potential biological activities have also been summarized in this review.

Catalytic asymmetric reactions and synthesis of quinones

Optically active 3,3-disubstituted oxindoles are obtained by a new organocatalyzed aerobic oxidative method.

Fei Xue

Papers

Catalytic and enantioselective α-functionalization of oxindoles through oxidative reactions with naphthoquinones.

Catalytic and Enantioselective α-Functionalization of Oxindoles Through Oxidative Reactions with Naphthoquinones.