321903-29-1

Using highly stable, readily accessible, and recyclable 2-(2-hydroxyprop-2-yl)cyclohexyl-substituted arylsilanes activated by a mild carbonate base, nickel-catalysed silicon-based aryl-aryl cross-coupling reaction proceeds for the first time with inexpensive aryl chlorides and tosylates in a highly chemoselective manner.

Aryl imidazylates are effective electrophilic partners in copper-free palladium-catalyzed Hiyama and Sonogashira cross-coupling reactions. The Sonogashira cross-coupling of estron-3-yl imidazylate afforded the corresponding phenylacetylene derivative in e

Through intramolecular activation, highly stable aryl[2-(hydroxymethyl) phenyl]dimethylsilanes can selectively transfer their aryl groups to effect a cross-coupling reaction with various aryl bromides and chlorides in the presence of a weak non-fluoride base and a palladium/copper catalyst. This reaction tolerates a wide range of functional groups, producing the corresponding functionalized biaryls in high yields with excellent chemoselectivity. Newly disclosed reaction conditions allow the recovery of a cyclic silyl ether in modest-to-good yields and reuse for the synthesis of the arylsilanes. The introduction of two isopropyl groups on the silicon center instead of methyl groups improves the stability and allows quantitative recovery of the silicon residue. Finally, aryl halides having an O-protected [2- (hydroxymethyl)phenyl] dimethylsilyl group cross-couple with the arylsilane reagents to give silyl-functionalized biaryls. Upon deprotection, the biaryls further react with the silylated electrophiles. The iterative cross-couplingdeprotection sequences allow rapid assembly of silylated oligoarenes. Syntheses of di- and trisilyloligoarenes are also achieved by use of orthogonal O-protecting groups.

In one embodiment of the present invention, a silicon-based cross-coupling reagent is disclosed which is a highly stable tetraorganosilicon compound allowing for a cross-coupling reaction under mild reaction conditions without using fluoride ions, transition metal promoter, or strong bases, and the residue of the silicon reagent can be recovered and reused. The silicon-based cross-coupling reagent is a silicon compound in which an o-hydroxymethylphenyl group is connected to a silicon atom for intramolecular activation.

The title reaction was found to proceed in the presence of a rhodium/1,2-bis(diphenylphosphino)benzene catalyst. Variously substituted arylethenes and 1,3-dienes were obtained in good yields. Georg Thieme Verlag Stuttgart.

The title reaction is found to proceed in the presence of a rhodium/diene catalyst. Variously substituted diarylmethylamines and allylamines having an N-arenesulfonyl protection are obtained in good yields, which are important building blocks in organic synthesis. Copyright

The title reaction is found to proceed in the presence of a palladium catalyst and in the absence of any activator. Various functional groups are tolerated to give a diverse range of 1,4-diene and diarylmethane products, which are ubiquitous units of natural products and pharmaceuticals. Copyright

Highly stable alkenyl[2-(hydroxymethyl)phenyl]dimethylsilanes are prepared by stereo- and regioselective hydrosilylation of alkynes catalyzed either by a platinum or ruthenium catalyst using protected [2-(hydroxymethyl)phenyl]dimethylsilanes. Cyclic silyl ether, 1,1-dimethyl-2-oxa-1-silaindan, also serves as a starting material for the alkenylsilanes by the ring-opening reaction with alkenyl Grignard reagents. The resulting alkenylsilanes undergo cross-coupling reaction with various aryl and alkenyl iodides under reaction conditions employing K2CO3 as a base at 35-50 °C in highly regio- and stereospecific manners. The reaction tolerates a diverse range of functional groups including silyl protections. The silicon residue is readily recovered and reused on a gram-scale synthesis. Intramolecular coordination of a proximal hydroxyl group is considered to efficiently form pentacoordinate silicates having a transferable group possibly at an axial position and, thus, responsible for the cross-coupling reaction under conditions significantly milder than those reported for the silicon-based reactions.

The alkoxides of o-silyl benzyl alcohols 4 undergo cleavage reactions under mild conditions allowing transfer of a benzyl or silyl group to an electrophile. Reactions 3a → 8, and 3c or 4c → 11 illustrate their potential as benzyl and silyl anion equivalents.