Application of chiral 2-isoxazoline for the synthesis of syn-1,3-diol analogs

• Juanjuan Feng,
• Tianyu Li,
• Jiaxin Zhang and
• Peng Jiao

Beilstein J. Org. Chem. 2019, 15, 1840–1847, doi:10.3762/bjoc.15.179

• product in 95% yield, which was converted into tert-butyl (3S,5R)-6-hydroxy-3,5-O-isopropylidene-3,5-dihydroxyhexanoate in 14 steps through a β-hydroxy ketone. Keywords: β-hydroxy ketone; cycloaddition; 1,3-diol; isoxazoline; silyl nitronate; Introduction The chiral 1,3-diol structure is widespread in a

• our continuous efforts in asymmetric syntheses and applications of chiral 2-isoxazolines [49][50][51]. Results and Discussion Our synthesis commenced with a chiral 3,5-disubstituted-2-isoxazoline 3 or 4, which were prepared from silyl nitronate through an asymmetric 1,3-dipolar cycloaddition developed

• established that 26 mol % of ligand B together with 20 mol % Cu(OTf)2 in anhydrous CH2Cl2 catalyzed the cycloaddition between N-acryloyl-1,3-oxazolidin-2-one and the silyl nitronate at −50 °C to give 1 in 95% isolated yield, which subsequently generated 3,5-disubstituted isoxazoline 4 in 80% ee. Decreasing

Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)

• Michał Nowacki and
• Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14

• indolylmethyl carbanion of the sulfone and 4-substituted nitrobenzenes is shown in Scheme 5. The formed σH-adduct A undergoes O-silylation and the formed silyl nitronate B is deprotonated to form intermediate C, that, after elimination of silanol, forms nitroso intermediate D. Consecutive silylation of D leads

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• organolithium reagent silyl nitronate 58 is deprotonated to give anion 60, which eliminates the silyloxy anion to form nitrosoalkene NSA12. Conjugate addition of the second equivalent of the organolithium compound furnishes oximes 59. However, oximes 59 are produced in rather poor yields. In 1996, Trost

• (+/−)-perhydrohistrionicotoxin. Addition of Gilman’s reagents to α,β-epoxy oximes 53. Addition of Gilman’s reagents to α-chlorooximes. Reaction of silyl nitronate 58 with organolithium reagents via nitrosoalkene NSA12. Reaction of β-ketoxime sulfones 61 and 63 with lithium acetylides. Electrophilic addition of nitrosoalkenes

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

• Yonglei Du,
• Jian Li,
• Kerong Chen,
• Chenglin Wu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

• -catalyzed Michael addition/intramolecular silyl nitronate-olefin cycloaddition (ISOC)/fragmentation sequence to produce highly enantioenriched spirocyclopentaneoxindoles containing an oxime functional group from easily accessible 3-allyl-substituted oxindoles and nitroolefins, which has received wide