Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• fragmentation rate constants or the N–O bond dissociation energies of radical anions and neutral radicals derived from RAEs are not available in the literature. Lumb and co-workers recently published a study on the conversion of biaryl-derived NHPI esters into spirocyclic cyclohexadienones through a

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• of 93:7 using ligand L25. Recently, Chegondi and co-workers have demonstrated an enantioselective Cu-catalyzed tandem borylation/Michael addition reaction of aryl enones 167 and 170 to cyclohexadienones in an intramolecular fashion (Scheme 43A) [84]. The 1,4-conjugate borylation is followed by a

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• yield was actually noted with (PhSe)2 as electrophile, 5 being obtained in 62% yield, enabling thus an evaluation of the next desymmetrization step. An overview of the scientific literature revealed that, while the asymmetric desymmetrization of prochiral 2,5-cyclohexadienones is a rich topic of

Breaking paracyclophane: the unexpected formation of non-symmetric disubstituted nitro[2.2]metaparacyclophanes

• Suraj Patel,
• Tyson N. Dais,
• Paul G. Plieger and
• Gareth J. Rowlands

Beilstein J. Org. Chem. 2021, 17, 1518–1526, doi:10.3762/bjoc.17.109

• highly oxidizing conditions, dehydrogenation of the resulting cyclohexadienol would give 11.The electron-rich 4-hydroxy[2.2]metaparacyclophane (9) participates in ortho selective nitration to give 5. Nitric acid has previously been used to oxidize phenols to cyclohexadienones [69][70], and a plausible

AgNTf₂-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives

• Ziping Cao,
• Jiekun Zhu,
• Li Liu,
• Yuanling Pang,
• Laijin Tian,
• Xuejun Sun and
• Xin Meng

Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255

• tethered to cyclohexadienones that can be converted into complex polycycles by Ag-carbenoid-initiated cascades [16]. Recently, Zhu’s group developed a tandem 1,3‑dipolar cycloaddition/cyclopropanation silver-catalyzed reaction of enynals with alkenes [17]. In our previous studies, this silver carbene

Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

• Matthew A. Horwitz,
• Elisabetta Massolo and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2017, 13, 762–767, doi:10.3762/bjoc.13.75

• Matthew A. Horwitz Elisabetta Massolo Jeffrey S. Johnson Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA 10.3762/bjoc.13.75 Abstract We report a desymmetrization of cyclohexadienones by intramolecular conjugate addition of a tethered dithiane

• nucleophile. Mild reaction conditions allow the formation of diversely functionalized fused bicyclic lactones. The products participate in facially selective additions from the convex surface, leading to allylic alcohol derivatives. Keywords: conjugate addition; cyclohexadienones; dearomatization

• ; desymmetrization; dithiane; iminophosphoranes; organocatalysis; phosphazenes; Findings Desymmetrization has become a well-developed strategy for the construction of complex molecular frameworks [1][2][3][4][5][6]. Cyclohexadienones are multipurpose synthetic building blocks that have found a central role in

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• the thiourea group interact with one or two carbonyl groups of phenylbutenoate 2 (Scheme 5). Another catalytic reaction catalyzed by a primary amine-thiourea that leads to multiple chiral centers is the asymmetric desymmetrization of 4,4-disubstituted cyclohexadienones 5, using the Michael addition of

• it near the enolate. In 2011, You and co-workers described the intramolecular desymmetrization of cyclohexadienones 69 catalyzed by thiourea 71, derived from cinchonine to give a bicyclic system 70 containing two chiral centers, utilizing an aza-Michael reaction (Scheme 24) [34]. The reaction

• -pyran-6-carboxylate 3 using organocatalyst 4 [16]. Possible hydrogen-bonding for the reaction of (E)-methyl 2-oxo-4-phenylbut-3-enoate [16]. Asymmetric desymmetrization of 4,4-cyclohexadienones using the Michael addition reaction with malonates [17]. The enantioselective synthesis of α,α-disubstituted