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Trifluoromethyl group diastereoselective reactions

Asymmetric hydrogenation of either a carbonyl or an imino group to a hydroxyl group or an amino group has frequently been employed for the introduction of chirality in amino acid syntheses. Corey s catecolborane-oxazaborolidine protocol enables transformation of difluoromethyl ketone 1 into alcohol 2 with excellent enantioselectivity. The reaction of diastereoselective amination of a-hydroxyaldehyde 3 with A,A-diallylamine and 2-furyl-boronic acid provides furyl amino alcohol 4 in good chemical yield along with excellent diastereoselectivity. This protocol is applicable for the preparation of amino acids and amino alcohols with a trifluoromethyl group by the combination of /V,/V-diallyl or N,N-dibenzyl amine and aromatic, heteroaromatic and alkenyl boronic acids [7]. The usual chemical transformations as shown in steps 5 to 8 in Scheme 9.1 lead to (2S,3R) difluorothreonine 5 [8]. [Pg.214]

The introduction of a nitro or trifluoromethyl group at the C-3 position on the pyridine ring in 3-(2-pyridylsulfinyl)acrylates has been shown to enhance the reactivity and diastereoselectivity of the dienophile in the Diels-Alder reaction with furan and its derivatives [171]. Such a modification of the dienophile renders the addition of diethylaluminium chloride unnecessary in order to achieve the desired asymmetric cycloaddition. The cycloadduct (207), prepared with high stereoselectivity from the asymmetric Diels-Alder reaction between (5)-menthyl 3-(3-trifluoromethylpyrid-2-ylsulfinyl)acrylate (194) and 2-methoxyfuran (208), was converted in seven steps to the glyoxalase I inhibitor (209) [171] (Scheme 5.67). [Pg.201]


See other pages where Trifluoromethyl group diastereoselective reactions is mentioned: [Pg.89]    [Pg.184]    [Pg.66]    [Pg.103]    [Pg.146]    [Pg.179]    [Pg.156]    [Pg.877]    [Pg.220]    [Pg.140]    [Pg.202]    [Pg.916]    [Pg.154]    [Pg.231]    [Pg.400]    [Pg.108]    [Pg.212]    [Pg.179]    [Pg.4]   


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Diastereoselective reaction

Diastereoselective reactions Diastereoselectivity

Diastereoselectivity groups

Diastereoselectivity reaction

Trifluoromethyl group

Trifluoromethyl groups reaction

Trifluoromethyl reactions

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