نتایج جستجو برای: annulation

تعداد نتایج: 988  

2013
Yan-Chao Shi Rong-Fei Yang De-Wei Gao Shu-Li You

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).

Journal: :Synthesis 2021

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...

Journal: :Chemical Science 2023

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.

Journal: :Organic & biomolecular chemistry 2011
Chih-Lung Chin Cheng-Feng Liao Hsing-Jang Liu Ying-Chieh Wong Ming-Tsang Hsieh Prashanth K Amancha Chun-Ping Chang Kak-Shan Shia

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.

Journal: :Organic & biomolecular chemistry 2011
Fang-gang Sun Song Ye

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.

Journal: :Organic & biomolecular chemistry 2013
Takanori Matsuda Norio Miura

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.

Journal: :Chemical communications 2010
Li Cui Longwu Ye Liming Zhang

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.

Journal: :Organic & biomolecular chemistry 2015
Takanori Matsuda Shoichi Watanuki

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.

Journal: :Chemical communications 2005
Dewen Dong Xihe Bi Qun Liu Fangdi Cong

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.

2018
Katharina Zielke Mario Waser

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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