نتایج جستجو برای: regioselective
تعداد نتایج: 2974 فیلتر نتایج به سال:
The total synthesis of (-)-cytoxazone 1 was achieved in six linear steps (34% overall yield) from p-anisaldehyde. The key steps in this route are the regioselective and stereoselective introduction of a N-protected amine group, using the CSI reaction of the anti-1,2-dimethyl ether 3, and the subsequent regioselective cyclization of the N-protected amino diol 13 to give the 2-oxazolidinone unit ...
2-Halogeno BODIPYs undergo copper catalysed nucleophilic substitution with alkyl amines and anilines and an amide to give the corresponding 3-aminoBODIPY derivatives. The substrates are readily prepared by the regioselective 2-halogenation of the chemically robust, preformed BODIPYs thus providing an alternative to direct nucleophilic substitution of the corresponding 3-halogenoBODIPYs which re...
A novel metal-free organobase-catalyzed regioselective benzoylation of diols and carbohydrates has been developed. Treatment of diol and carbohydrate substrates with 1.1 equiv. of 1-benzoylimidazole and 0.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in MeCN under mild conditions resulted in highly regioselective benzoylation for the primary hydroxyl group. Importantly, compared to most ...
Cross-dehydrogenative couplings of two different C-H bonds have emerged as an attractive goal in organic synthesis. However, achieving regioselective C-H activation is a great challenge because C-H bonds are ubiquitous in organic compounds. Actually, the regioselective couplings promoted by enzymes are a common occurrence in nature. Herein, we have developed simple, efficient and general transi...
the use of methanesulfonic acid as a brønsted acid for direct ortho-acylation of phenols and naphthols proves to be a convenient, more general and direct route to various hydroxyaryl ketones. the route is regioselective, leading to ortho c-acylated products in satisfactory to high yields in most cases. the solvent free reactions described below exhibited environmentally benign in terms of faste...
Gold(i) catalyses the ring-opening addition of cyclopropenes in a mild and regioselective manner.
epoxides undergo regioselective ring opening with various nucleophiles using catalytic amount of nano magnesium oxide and water as solvent under mild reaction conditions. the remarkable features of this method are improved yields, high regioselectivity, and green chemistry agreement.
Regioselective and stereospecific directed C–H arylation of simple amine substrates, cyclisation, delivered 30 diverse, three-dimensional scaffolds.
1,4-bis(triphenylphosphonium)-2-butene dichloride was developed as a new phase transfer catalyst. This quaternized phosphonium salt catalyzed the regioselective ring opening of epoxides by thiocyanate ion to give β-hydroxy thiocyanates in high yields under mild conditions.
A series of functionalised aromatic boronic esters have been prepared via the regioselective cycloaddition of 2-pyrones with alkynylboronates.
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