نتایج جستجو برای: annulation
تعداد نتایج: 988 فیلتر نتایج به سال:
When Boc-L-Val-OH was used as a ligand for the enantioselective Pd(II)-catalyzed annulation of N,N-substituted aminomethyl ferrocene derivatives with diarylethynes, ferrocenes with planar chirality could be achieved with excellent enantioselectivity (up to 99% ee).
Abstract Bicyclic alkenes, including oxa- and azabicyclic readily undergo activation with facial selectivity in the presence of transition-metal complexes. This is due to intrinsic angle strain on carbon–carbon double bonds such unsymmetrical bicyclic systems. During past decades considerable progress has been made area ring opening strained rings by employing concept C–H activation. short revi...
Innovative Mn( iii )-mediated intramolecular C–P bond activation and annulation in diphosphines via a radical passway were established understood. All ionic products had excellent fluorescence circularly polarized luminescence activity.
Under catalysis with ZnI(2), an effective annulation process of ω-silylacetylenic α-cyano ketones, leading to the formation of various bicyclic frameworks characterized with a TMS-containing methylenecyclopentane ring, has been developed.
The diastereoselective synthesis of cis-2-amino-3-hydroxyindanones was realized by the N-heterocyclic carbene-catalyzed [4 + 1] annulation of phthalaldehyde and imines, which may involve a tandem aza-benzoin reaction and aldol reaction.
A formal [4 + 2] annulation occurs between 1,3-disubstituted cyclobutenols and internal alkynes in the presence of rhodium(I) catalysts to afford 1,2,3,5-tetrasubstituted benzenes. These benzannulation products are generated through dehydration of the initially formed cyclohexadienols.
A surprisingly efficient synthesis of azepan-4-ones via a two-step [5 + 2] annulation is developed. This reaction involves a key gold catalysis and shows generally high regioselectivities and good to excellent diastereoselectivities.
The rhodium(I)-catalysed arylative annulation of 1,4-enynes with arylboronic acids was investigated. The reaction was found to proceed via an addition-1,4-rhodium migration-addition sequence, affording the corresponding 1,1-disubstituted 3-(arylmethylene)indanes.
A novel and facile route to functionalized mono/bicyclic 2,3-dihydro-4-pyridones has been developed via formal [5C + 1N] annulation of readily available alpha-alkenoyl ketene-(S,S)-acetals with various aliphatic primary amines.
The first (4 + 1)-annulation of o-quinone methides with α-branched allenoates as C1 synthons has been developed. This operationally simple protocol gives access to highly functionalized dihydrobenzofurans in an unprecedented fashion with excellent diastereoselectivities and high yields.
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