نتایج جستجو برای: dihydropyran

تعداد نتایج: 69  

Journal: :Organic & biomolecular chemistry 2015
Paul A Clarke Philip B Sellars Nadiah Mad Nasir

The Maitland-Japp reaction has been extended to the synthesis of highly functionalised dihydropyran-4-ones. These dihydropyran-4-ones can in turn be converted stereoselectively into tetrahydropyran-4-ones with tertiary and quaternary stereocentres via the one-pot addition of hydride or carbon nucleophiles and trapping with carbon electrophiles. The utility of this method is demonstrated by prov...

Journal: :Organic & biomolecular chemistry 2012
Cheng-Kui Pei Yu Jiang Min Shi

β-Isocupreidine (β-ICD) catalyzed asymmetric [4 + 2] cycloaddition of β,γ-unsaturated α-ketoesters with allenic esters afforded ester-substituted functionalized dihydropyran derivatives in high yields along with high enantioselectivities under mild conditions.

Journal: :Chemical communications 2014
Pandurang V Chouthaiwale Fujie Tanaka

Concise cascade reactions of pyruvates with aldehydes that generate functionalized dihydropyran derivatives in one pot have been developed. The products, dihydropyrans, were further concisely transformed to various molecules.

Journal: :The Journal of the Society of Chemical Industry, Japan 1962

Journal: :The Journal of the Society of Chemical Industry, Japan 1964

Journal: :Canadian Journal of Chemistry 1965

Journal: :The Journal of the Society of Chemical Industry, Japan 1964

Journal: :Journal of the American Chemical Society 2001
D A Evans K A Scheidt J N Johnston M C Willis

The scope of highly enantioselective and diastereoselective Michael additions of enolsilanes to unsaturated imide derivatives has been developed with use of [Cu((S,S)-t-Bu-box)](SbF6)2 (1a) as a Lewis acid catalyst. The products of these additions are useful synthons that contain termini capable of differentiation under mild conditions. Michael acceptor pi-facial selectivity is consistent with ...

Journal: :Organic & biomolecular chemistry 2012
Cheng-Kui Pei Lei Wu Zhong Lian Min Shi

Highly efficient DABCO-catalyzed [4 + 2] cycloaddition of β,γ-unsaturated α-ketophosphonates or β,γ-unsaturated α-ketoesters with allenic esters gives the corresponding highly functionalized tetrahydropyran and dihydropyran derivatives in good to excellent yields and moderate to good regioselectivities under mild conditions.

Journal: :Chemical communications 2015
Bjarke S Donslund Alicia Monleón Jesper Larsen Lise Ibsen Karl Anker Jørgensen

The highly enantioselective dienamine-mediated formation of 5-bromo-6-(trifluoromethyl)-3,4-dihydro-2H-pyrans from α,β-unsaturated aldehydes and α-bromo-(trifluoromethyl)-enones employing a C2-symmetric aminocatalyst is described. The products are demonstrated to be applicable in coupling reactions directly onto the ring, thereby granting access to a broad scope of highly substituted 6-(trifluo...

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