- General and efficient insertions of carbons carrying aryl and heteroaryl groups: Synthesis of α-Aryl- And α-heteroaryl-substituted ketones
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Anions formed from the lithiation of a variety of 1-(arylmethyl)- and 1-(heteroarylmethyl)-benzotriazoles 1 with n-BuLi underwent addition to aliphatic and aromatic aldehydes and cyclic and acyclic ketones. Subsequent in situ thermal rearrangements of the intermediates in the presence of zinc bromide provided one-carbon chain-extended or ring-expanded α-aryl- and α-heteroaryl-substituted ketones 2 in moderate to excellent yields in simple one-pot operations with excellent regioselectivity in most cases. Substituent effects on the relative migration rates were investigated in the insertion reactions of 1-(4-methoxybenzyl)benzotriazole (1e) with XC6H4-COPh. The small and negative Hammett ρ+ value (-0.92) suggested that the rearrangements proceed via early, reagent-like, electron deficient transition states.
- Katritzky, Alan R.,Toader, Dorin,Xie, Linghong
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- A photoinduced, benzyne click reaction
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The [3 + 2] cycloaddition of azides and alkynes has proven invaluable across numerous scientific disciplines for imaging, cross-linking, and site-specific labeling among many other applications. We have developed a photoinitiated, benzyne-based [3 + 2] cycloaddition that is tolerant of a variety of functional groups as well as polar, protic solvents. The reaction is complete on the minute time scale using a single equivalent of partner azide, and the benzyne photoprecursor is stable for months under ambient light at room tempurature. Herein we report the optimization and scope of the photoinitiated reaction as well as characterization of the cycloaddition products.
- Gann, Adam W.,Amoroso, Jon W.,Einck, Vincent J.,Rice, Walter P.,Chambers, James J.,Schnarr, Nathan A.
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p. 2003 - 2005
(2014/05/06)
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- Reactivity of AllylSmBr/HMPA: Facile Synthesis of 3-Aryl-1,2,4- benzotriazines
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3-Aryl-1,2,4-benzotriazines were conveniently prepared in moderate to good yields from 1,l-bis(benzotriazol-1-yl)methylarenes with allylsamarium bromide/hexamethylphosphramide (allylSmBr/HMPA). Preliminary results indicate that HMPA may enhance the reduci
- Yin, Ruifeng,Zhou, Liejin,Liu, Huili,Mao, Hui,Lue, Xin,Wang, Xiaoxia
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p. 143 - 148
(2013/08/24)
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- The Mitsunobu reaction: An alternative synthesis of 1-(primary alkyl)benzotriazoles
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1-(Primary alkyl)benzotriazoles are obtained in convenient yields by treating the corresponding alcohol with triphenylphosphine, N-bromosuccinimide and benzotriazole. Under these conditions, the alcohols gave exclusively the corresponding 1-alkyl-benzotriazoles. Allyl and propargyl alcohols also reacted regiospecifically in a typical S(N)2 manner, and no products derived from prototropic rearrangement were found.
- Katritzky, Alan R.,Oniciu, Daniela C.,Ghiviriga, Ion
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p. 1613 - 1621
(2007/10/03)
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