Silver-Catalyzed Reaction of Enynals with Alkenes: A Tandem 1,3-Dipolar Cycloaddition/Cyclopropanation
作者:Renxiao Liang、Tongmei Ma、Shifa Zhu
DOI:10.1021/ol5017299
日期:2014.9.5
silver-catalyzed reaction of enynals with alkenes to synthesize a series of polycyclic compounds has been developed. The reaction occurred smoothly using enynals with electron-deficient alkynes or terminal alkynes as substrates. The reaction was proposed to proceed through a tandem 1,3-dipolar cycloaddition/cyclopropanation process. The preliminary investigations of the asymmetric catalytic version revealed that
An efficient and mild synthesis of imidazo[1,2-a]pyrimidine derivatives has been developed from readily available pyrimidyl arylamines or enamines through a hypervalent iodine-promoted intramolecular C–H bond cycloamination reaction. This protocol allows for the facile construction of biologically active bicyclic imidazo[1,2-a]pyrimidine skeletons as well as other imidazo[1,2-a]-type fused heterocycles
intermolecular additions of propiolate esters with alcohols. The reaction of propiolate esters and alcohols in the presence of PtCl2 gave (E)-vinyl ethers as the major products at 60 °C, whereas alkyl 3,3-dialkoxypropanoates were predominantly obtained when the reaction temperature was set to 80 °C. On the other hand, a novel regioselective tetramerization of propiolate esters catalyzed by AuCl3 under
The invention relates to fragrance precursors, In particular, the invention relates to the use of several classes of compounds which may act as fragrance precursors, e,g., in cosmetic products such as deodorants and antiperspirants and in laundry products such as detergents and fabric softners. These compounds are odorless, but upon contacting the skin as example, in skin care compositions or in personal care compositions, produce fragrances. The compounds also produce fragrances when used in the presence of lipases, e.g. as used in (laundry) detergents, thus providing a prolongation of the fabric scenting effect. The compounds under consideration are compounds of the formula I:
The substituents are defined in the specification.
Enantioselective Synthesis of β-Allenoates via Phosphine-Catalyzed and ZnI<sub>2</sub>-Promoted Preparation of Oxazolidines and Propargylamines Using Chiral Amines, 1-Alkynes, and Propiolates
Diphenylphosphinoethane (DPPE)-catalyzed and ZnI2-promoted in situ formation of oxazolidine, alkynyl zinc, and propargylamine intermediates from 1-alkynes, chiral (S)-diphenyl(pyrrolidin-2-yl)methanol, and propiolates gave the corresponding chiral (R)-β-allenoates in 40–72% yield with up to >99% ee. The intermediate propargylamine was isolated in 50% yield and converted to give the β-allenoate 10aa