120 research outputs found
CsF–Al<SUB>2</SUB>O<SUB>3</SUB> mediated rapid condensation of phenols with aryl halides: comparative study of conventional heating vs. microwave irradiation
Biaryl ethers and thio ethers are formed in high yields by the condensation of phenols and thiophenols with electron-deficient aryl halides using CsF supported on Al2O3 under microwave irradiation in solvent-free conditions
Short-route synthesis of (3E,5Z)-tetradecadienoic acid (megatomic acid), the sex attractant of the black carpet beetle
A new and expeditious route to (3E,5Z)-3,5-tetradecadienoic acid (megatomic acid), the sex attractant of the black carpet beetle Attagenus megatoma (Fabricius), is reported which proceeds with 97% stereoselectivity; Cadiot-Chodkiewicz cross-coupling of 1-decyne and 4-bromo-3-butyn-1-ol in the presence of CuCl, followed by stereoselective reductions and Jones oxidation, gives the target molecule, with the synthetic pheromone showing a positive electrophysiological response
Metal triflates catalyzed efficient synthesis of 3,4-dihydro-2H-1-benzopyrans
Ytterbium triflate efficiently catalyzes an unusual cyclization of o-hydroxybenzaldehydes with 2,3-dihydrofuran and 3,4-dihydro-2H-pyran in the presence of trimethyl orthoformate at ambient temperature to afford a new class of compounds, furo- and pyrano[2,3-b]benzopyrans in excellent yields with high diastereoselectivity. Also, o-hydroxybenzaldehydes reacted smoothly with acetophenones in the presence of a catalytic amount of scandium triflate under similar reaction conditions to give the corresponding 2,4-dialkoxy-2-aryl-3,4-dihydro-2H-1-benzopyrans in high yields
Stereoselective total synthesis of polyketide lactone,(3R, 4S, 5S, 9S)-3, 5, 9-trihydroxy-4-methylundecanoic acid [delta]-lactone
The total synthesis of lactone 1 has been described. The convergent asymmetric synthesis relies on the use of an Evans' syn-aldol, chain extension with lithio tert-butyl acetate, and the stereoselective reduction of a ketone as the key reactions
InBr<SUB>3</SUB>-catalyzed Ferrier rearrangement: an efficient synthesis of C-pseudoglycals
Glycals react smoothly with silyl nucleophiles such as allyltrimethylsilane, trimethylsilyl cyanide and trimethylsilyl azide in the presence of a catalytic amount of indium tribromide to give the corresponding 2,3-unsaturated allyl glycosides, glycosyl cyanides and glycosyl azides in excellent yields with high α-selectivity
A concise total synthesis of diospongins A and B
The total synthesis of the diarylheptanoids (-)-diospongin A (1) and B (2) was achieved stereoselectively via the δ-lactone intermediate 6. The key reactions involved are a stereoselective reduction of β-keto ester and the Horner-Wadsworth-Emmons and intramolecular oxy-Michael reactions
Total synthesis of the marine polypropionaes, siphonarienal, siphonarienone and pectinatone
The synthesis of the marine natural products, siphonarienal, siphonarienone, and pectinatone is described employing desymmetrization strategy to create three consecutive stereogenic centers. The key intermediate 7 was made by asymmetric hydroboration of the known meso-olefin using (-)-IPC<SUB>2</SUB>BH followed by PCC and Baeyer-Villiger oxidation reactions
Total Synthesis of a Diacetonide Derivative of Thuggacin A
A highly
stereoselective total synthesis of the diacetonide derivative
of the antibiotic thuggacin A has been described. The synthesis features
the stereoselective Stille cross-coupling reaction to set up the whole
carbon framework, aldol condensation to construct the highly substituted
conjugated diene, non-Evans <i>syn</i> aldol, CBS reduction,
Hantzsch’s thiazole synthesis, Horner–Wadsworth–Emmons
reaction, and Shiina’s macrolactonization
Soybean lipoxygenase and horseradish peroxidase catalysed asymmetric oxidation-reduction sequence for the synthesis of chiral (Z,E) diene-diols
Unnatural synthetic substrates with a properly spaced prosthetic modifier having non-ionic hydroxy terminus undergoes soybean lipoxygenase catalysed asymmetric peroxidation followed by horseradish peroxidase induced reduction affords (Z, E)-diene-diol in high enantiomeric excess
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