Asymmetric Synthesis of Trifluoromethylated ent‐Fragransin C₁

Abstract

Asymmetric synthesis of trifluoromethylated derivative of ent‐fragransin C1 was reported. The installation of contiguous stereochemistries across the tetrahydrofuran scaffold was achieved through stereocontrolled conjugate addition, aldol reaction, and a protection‐free intramolecular C‐O bond formation (furan ring formation) via chemoselective generation of the benzylic carbocation.

Base catalyzed one-pot thia-Michael addition-oxidation reaction of hetero-aromatic thiols to 2-aryl-3-nitro-2H-chromenes and their antibacterial evaluation

“…Our initial investigative work commenced with the establishment of the feasible strategy and optimization of the thia-Michael addition reaction of heteroaromatic thiols to 3-nitro-2-phenyl-2H-chromene as model substrates. 27 After acquiring the requisite starting materials in hand, the effectiveness of the one-pot thia-Michael addition reaction of the heteroaromatic thiols to 3-nitro-2H-chromenes was evaluated by altering different parameters, including the base, temperature, amount of time, and various solvent mediums.…”

“…22 There have been a few other instances of Michael addition reactions between thiophenol to 1-nitrocyclohexene and various a,b-unsaturated compounds. [23][24][25][26][27] However, to our knowledge, the thia-Michael addition has been less explored as compared to the aza-Michael addition reaction. Moreover, there is no documented instance of a thia-Michael addition reaction between heterocyclic thiols and conjugated cyclonitroolefins.…”

Base-catalyzed diastereodivergent thia-Michael addition to chiral β-trifluoromethyl-α,β-unsaturated N-acylated oxazolidin-2-ones

“…We first investigated the reaction of ( R , E )-4-phenyl-3-(4,4,4-trifluorobut-2-enoyl)oxazolidin-2-one ( 1 ) 13 employing thiophenol ( 2a ) as a nucleophile. The results are summarized in Table 1.…”

Bioinspired stereoselective synthesis of chiral 2,5-diaryl-3,4-dimethyltetrahydrofurans from unprotected 1,4-diarylbutane-1,4-diols

“…[11][12][13][14][15] With an atom-economy concern, a synthetic strategy that allows simple and direct transformation of chiral 1,4-diarylbutane-1,4-diols B to chiral 2,5-diaryl-3,4-dimethyltetrahydrofurans in a chemo-and stereoselective manner is highly desirable and deserves investigation. 16,17 Having been interested on the synthetic approach to access chiral 2,5-diaryl-3,4-dimethyltetrahydrofurans bearing 2,3-anti-3,4-syn-4,5-anti relative stereochemistry, [18][19][20][21] we primarily investigated an acid-catalyzed reaction of chiral 1,4-diarylbutane-1,4-diols 1 and 2. The results from this work would provide an insight on the factors that govern chemoselective formation of carbocations followed by their stereoselective cyclization reactions to chiral 1,4-diarylbutane-1,4-diols 1 and 2 (Scheme 2c).…”