نتایج جستجو برای: diastereoselectivity

تعداد نتایج: 565  

Journal: :Organic letters 2011
Jenny B Werness Weiping Tang

A stereoselective total synthesis of (-)-kumausallene was completed in 12 steps from acetylacetone. The hidden symmetry of (-)-kumausallene was recognized, and its skeleton was constructed efficiently from a C(2)-symmetric diol by a palladium-catalyzed cascade reaction. High diastereoselectivity was observed for the DMF-promoted biomimetic 1,4-bromocyclization of a conjugated enyne.

2014
Cristian Soldi Kellan N. Lamb Richard A. Squitieri Marcos González-López Michael J. Di Maso Jared T. Shaw

The first asymmetric insertion reactions of donor-donor carbenoids, i.e., those with no pendant electron-withdrawing groups, are reported. This process enables the synthesis of densely substituted benzodihydrofurans with high levels of enantio- and diastereoselectivity. Preliminary results show similar efficiency in the preparation of indanes. This new method is used in the first enantioselecti...

Journal: :Chemical communications 2016
Zhan-Yong Wang Ya-Li Ding Gang Wang Ying Cheng

The chiral N-heterocyclic carbene/Lewis acid co-catalyzed reaction of 2-aroylvinylcinnamaldehydes produced good yields of indeno[1,2-c]furan-1-one derivatives with excellent enantioselectivity and diastereoselectivity. A switch of intramolecular cyclization to intermolecular dimerization was achieved by the cooperative catalysis of chiral triazole carbene and Ti(OPr-i)4 catalysts.

Journal: :Organic & biomolecular chemistry 2014
M Kamlar S Hybelbauerová I Císařová J Veselý

The highly stereoselective allylic alkylation of Morita-Baylis-Hillman carbonates with β-ketoesters catalysed by β-ICD is described. The corresponding products containing two adjacent quaternary and tertiary carbon centers were obtained in good yields with high diastereoselectivity (up to 10 : 1 dr) and enantioselectivity (up to 95% ee).

Journal: :Organic letters 2002
David A Evans C Wade Downey Jared T Shaw Jason S Tedrow

[reaction: see text] Diastereoselective direct aldol reactions of chiral N-acylthiazolidinethiones occur in high yield with preference for the illustrated anti diastereomer. This reaction is catalyzed by 10% MgBr2.OEt2 in the presence of triethylamine and chlorotrimethylsilane. Yields range from 56 to 93% with diastereoselectivity up to 19:1 for a variety of N-acylthiazolidinethiones and unsatu...

Journal: :Organic letters 2013
Kengo Akagawa Shota Takigawa Iman Sho Nagamine Ryota Umezawa Kazuaki Kudo

Highly diastereo- and enantioselective cyclopropanation of aromatic α,β-unsaturated aldehydes was achieved using a resin-supported peptide catalyst under aqueous conditions. In the peptide sequence, the residue possessing an oxygen atom with the appropriate length of the side chain was essential for attaining good diastereoselectivity.

2016
Adam Throup Laurence H Patterson Helen M Sheldrake

Fused cyclobutanes are found in a range of natural products and formation of these motifs in a straightforward and easy manner represents an interesting synthetic challenge. To this end we investigated an intramolecular variant of the thermal enamine [2 + 2] cyclisation, developing a diastereoselective intramolecular enamine [2 + 2] cyclisation furnishing δ lactone and lactam fused cyclobutenes...

Journal: :Chemical communications 2011
Ming-Qing Hua Lian Wang Han-Feng Cui Jing Nie Xiao-Ling Zhang Jun-An Ma

An efficient, catalytic, diastereo- and enantioselective conjugate addition of N-(diphenylmethylene)glycine tert-butyl ester to β-aryl substituted enones was realized in the presence of 1 mol% of newly desired dinuclear N-spiro-ammonium salts, affording functionalized α-amino acid derivatives in 57-98% yields with high diastereoselectivity (up to 99:1 dr) and enantioselectivity (up to 96.5:3.5 ...

Journal: :Chemistry, an Asian journal 2012
Sang-Shin Lee Won-Yeob Kim Hee-Yoon Lee

Total synthesis of ceratopicanol (1) was achieved with a tandem cycloaddition reaction of allenyl diazo compound 6 via a trimethylenemethane (TMM) diyl intermediate. The TMM diyl mediated [2+3] cycloaddition reaction furnished the consecutive quaternary carbon centers and showed an unusual diastereoselectivity.

Journal: :Chemical communications 2014
Amlan K Pal Philippe D Ducharme Garry S Hanan

The diastereoselective formation of a meso-dinuclear Ru(ii) complex of a novel bis-bidentate ligand is reported along with its electrochemical and photophysical properties. The design of the ligand, with its parallel coordination vectors, induces a diastereoselectivity of 1 : 13 : 1 [ΛΛ : (ΛΔ or ΔΛ) : ΔΔ] for the dinuclear complex.

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید