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

• Juanjuan Feng Tianyu Li Jiaxin Zhang Peng Jiao Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China 10.3762/bjoc.15.179 Abstract The asymmetric cycloaddition of TIPS nitronate catalyzed by “Cu(II)-bisoxazoline” gave the 2-isoxazoline

• chiral β-hydroxy-δ-lactone moiety or its equivalents, pioneered by Wong [42], is equally competitive. Here, we report the preparations of tert-butyl (3S,5R)-6-hydroxy-3,5-O-isopropylidene-3,5-dihydroxyhexanoate and related syn-1,3-diol analogs from a chiral 2-isoxazoline (Scheme 1b). This work is part of

• 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

Hypervalent iodine-mediated Ritter-type amidation of terminal alkenes: The synthesis of isoxazoline and pyrazoline cores

• Sang Won Park,
• Soong-Hyun Kim,
• Jaeyoung Song,
• Ga Young Park,
• Darong Kim,
• Tae-Gyu Nam and
• Ki Bum Hong

Beilstein J. Org. Chem. 2018, 14, 1028–1033, doi:10.3762/bjoc.14.89

• -type oxyamidation and amido-amidation protocol in the presence of a Lewis acid. This transformation provides direct access to diverse 5-acetaminomethyl substituted 2-isoxazoline/2-pyrazoline derivatives using acetonitrile as both the solvent and amine source. Hypervalent iodine-mediated

N–O Cleavage reactions of heterobicycloalkene-fused 2-isoxazolines

• Jaipal R. Nagireddy,
• Geoffrey K. Tranmer,
• Emily Carlson and
• William Tam

Beilstein J. Org. Chem. 2014, 10, 2200–2205, doi:10.3762/bjoc.10.227

• yields (66–95%) and without the need for chromatographic purification. Keywords: azabicycloalkene; β-hydroxyketone; 2-isoxazoline; oxabicycloalkene; Raney nickel; Introduction 2-Isoxazolines 1 are practical precursors to countless structural motifs found in nature. Various carbonyl compounds 2, β

• as β-hydroxycarbonyl derivatives 12 and γ-aminoalcohols 13, as well as carbonyl compounds including phthalan 14 and isoindoline derivatives 15 (R2 = Ar; Scheme 2). Results and Discussion For our investigation of heterobicycloalkene-fused 2-isoxazoline cleavage, we initially planned to follow our

• of 2-isoxazoline rings fused to oxabicyclic and azabicyclic frameworks, which show novel reactivity compared to our former report of carbobicyclic analogues. The transformation involves N–O bond cleavage of the 2-isoxazoline followed by imine hydrolysis, leading to β-hydroxyketone products with

A one-pot synthesis of 3-trifluoromethyl-2-isoxazolines from trifluoromethyl aldoxime

• Raoni S. B. Gonçalves,
• Michael Dos Santos,
• Guillaume Bernadat,
• Danièle Bonnet-Delpon and
• Benoit Crousse

Beilstein J. Org. Chem. 2013, 9, 2387–2394, doi:10.3762/bjoc.9.275

• optimized reagents and conditions, the scope of the reaction was explored with regard to the substrates (Table 2). As observed in the earliest works [11], the cycloaddition of 4 with terminal olefins led to the corresponding 3-trifluoromethyl-5-substituted-2-isoxazoline 1 with complete regioselectivity. No

• trace of the regioisomer 3-trifluoromethyl-4-substituted-2-isoxazoline could be detected even when yields of cycloadducts were low. From functionalized olefins such as NH–Cbz and NH–Boc allylamines the desired product could be isolated in excellent yields (90% and 91%, respectively, Table 2, entries 2

• different fluorinated building blocks was demonstrated by the easy ring opening of these intermediates with NaBH4 and NiCl2, yielding the corresponding trifluoromethylated γ-amino alcohol. Example of bioactive molecules bearing the 2-isoxazoline nucleus. Dimerization and isomerization products from nitrile

Photocycloaddition of aromatic and aliphatic aldehydes to isoxazoles: Cycloaddition reactivity and stability studies

• Axel G. Griesbeck,
• Marco Franke,
• Jörg Neudörfl and
• Hidehiro Kotaka

Beilstein J. Org. Chem. 2011, 7, 127–134, doi:10.3762/bjoc.7.18

• evaporated. The crude product was obtained as a yellow oil and used immediately without further purification. 3-Methyl-5-trimethylsilyloxy-2-isoxazoline (2) [19]. A mixture of acrylonitrile (10.61 g, 0.2 mol, 13.2 mL), triethylamine (10.12 g, 0.1 mol, 13.9 mL) and 1 (28.73 g, 0.2 mol) in toluene (90 mL) was