Enantioselective aldol reactions of α,β-unsaturated ketones with trifluoroacetophenone catalyzed by a chiral primary amine

Enantioselective Synthesis of Tertiary Trifluoromethyl Carbinols by Vinylogous Aldol Reaction of 3-Methylcyclohex-2-en-1-one with (Het)aryl Trifluoromethyl Ketones

“…ee. 14 Recently, Da and co-workers demonstrated a chiral thiourea-mediated cross-aldol reaction between hydroxyacetophenones and trifluoromethyl ketones, the first example of the use of an aryl ketone in a direct asymmetric aldol reaction. 15 The vinylogous process has proven to be a powerful strategy for the direct γ-carbon functionalization with a high level of structural complexity.…”

Trifluoroacetylation of electron-rich thiophenes

“…Trifluoroacetylated thiophenes are useful intermediates in organic chemistry and have, for example, been utilized in the preparation of biological active compounds [9,10] in polymer chemistry [11,12], in asymmetric syntheses [13][14][15][16] and in palladium catalyzed coupling reactions [17,18]. We needed trifluoroacetylated thiophenes as a part our investigations on biofilm inhibitors [19] and were interested in the trifluoroacetylation of thiophenes having strong electron-donating substituents.…”

Catalytic Enantioselective Oxa-Hetero-Diels-Alder Reactions of Enones with Aryl Trifluoromethyl Ketones: Synthesis of Tetrahydropyranones

“…3 Further, reactions of enones with ketones or aldehydes often afford aldol products as the main products. [5][6][7] We hypothesized that additional evaluations of primary amine derivatives with or without acids under various conditions 2a-c would identify catalyst systems suitable for the oxa-hetero-Diels-Alder reactions affording the other type of tetrahydropyranone diastereomers as the main products with high diastereo-and enantioselectivities. Amine derivatives were evaluated in the catalysis of the reaction of enone 1a with 2,2,2-trifluoroacetophenone (2a) to afford tetrahydropyranone derivative 3a-1 as the main product in a high yield with high diastereo-and enantioselectivities; selected results are shown in Table 1 (full results will be published in the future).…”

“…The absolute configuration of the major diastereomer of 3a (i.e., 3a-1) was determined to be (R,R) as shown in Table 2 by correlating with (R,R)-3a-1 obtained from (R)-4a 6 by an acid-catalyzed oxa-Michael cyclization 9 (Scheme 2).…”