Search

A variety of 1,3-disubstituted naphthalenes have been prepared by palladium-catalyzed annulation of (o -ethynylphenyl)acetyl chloride with design of a new synthetic strategy by Stille coupling using functionalized organostannanes. The method affords excellent yields of the substituted naphthalenes and accommodates a wide variety of functional groups under mild conditions. Mechanistic studies show intramolecular cyclization as a major step following C–C bond coupling. [ABSTRACT FROM AUTHOR]

A new synthesis of pyrazolo[4,3-d]pyrimidines and isoxazolo[4,5-d]pyrimidines is described. Key steps in the synthesis involve Stille coupling of 4,6-dichloro-2-phenyl-pyrimidine with tributyl(1-ethoxyvinyl)stannane and tandem Schiff-base formation/heterocyclization of 2,6-di-aryl-5-fluoro-4-acetylpyrimidine with hydrazines or -hydroxylamine to give pyrazolo[4,3-d]pyrimidines and isoxazolo[4,5-d]pyrimidines, respectively. The position of the fluoro group in the -pyrimidine ring is important for the success of heterocylization reaction. [ABSTRACT FROM AUTHOR]

The C1–C17 segment of bafilomycin N has been synthesized. The C1–C11 segment was synthesized by the anti -selective vinylogous Mukaiyama aldol reaction with a chiral vinylketene silyl N , O -acetal and the Horner–Wadsworth–Emmons reaction, whereas C12–C17 was constructed by the syn -selective vinylogous Mukaiyama aldol reaction and the Jung's semipinacol rearrangement. Those segments were connected by the Stille coupling to afford the C1–C17 segment. [ABSTRACT FROM AUTHOR]

Various alkoxy-substituted heterocyclic stannanes provide access to the corresponding substituted 'pyridone' moieties via Stille cross-coupling. Both pyridyl and a series of diazinyl stannanes are prepared, and options for unmasking (via demethylation or debenzylation) of the pyridone unit are evaluated. [ABSTRACT FROM AUTHOR]

Starting from unsymmetrically O-protected methyl 4- bromo-3,5-dihydroxybenzoate, a facile synthesis of the methyl ether of bioactive natural product NG-121 was accomplished in very good overall yield. The key steps were: Stille coupling reaction of the farnesyl unit with the electron-rich phenolic segment; hydroxy- directed selective epoxidation of the farnesyl chain along with concomitant phenol-driven intramolecular regio- and diastereoselective ring closure to the corresponding hydroxybenzopyran; and regioselective formylation followed by in situ reductive lactonization. [ABSTRACT FROM AUTHOR]

An effective room-temperature Stille cross-coupling of aryl ureas with tetraarylstannanes via palladium-catalyzed C-H bond activation is reported, providing a mild method for direct arylation of aromatic C-H bonds. [ABSTRACT FROM AUTHOR]

The orally active, noncompetitive, selective AMPA receptor antagonist Perampanel, 2-[1',6'-dihydro-6'-oxo-1-phenyl-(2',3'-bipyridin)-5'-yl]benzonitrile, has been prepared from readily available, relatively inexpensive starting materials. The synthesis was carried out on a laboratory scale with no specialized equipment, and involved only two chromatographic purifications. [ABSTRACT FROM AUTHOR]

Aryl stannanes are easily accessible from o-silylated aryl triflates in the presence of KF and Bu3SnH. The corresponding arynes are formed in situ, and undergo clean hydrostannation to give a mixture of the regioisomeric aryl stannanes. The whole reaction sequence can also be carried out as a one-pot reaction under microwave irradiation. [ABSTRACT FROM AUTHOR]

We established a synthetic method for the chemical isostere of the structurally unique natural product, 4′-O-methyl honokiol by replacing two allyl groups with two different alkyl groups with the aim of developing synthetic analogues of the chemical isostere. The key steps in this synthetic route are the Suzuki-Miyaura coupling reaction for the formation of the phenylpyridine moiety and the Stille coupling reaction for the stepwise introduction of two allyl groups. [ABSTRACT FROM AUTHOR]