- Chemoselective palladium-catalyzed deprotonative arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers
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Control of chemoselectivity is one of the most challenging problems facing chemists and is particularly important in the synthesis of bioactive compounds and medications. Herein, the first highly chemoselective tandem C(sp3)-H arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers is presented. The efficient and operationally simple protocols enable generation of either arylation products or tandem arylation/[1,2]-Wittig rearrangement products with remarkable selectivity and good to excellent yields (60-99%). Choice of base, solvent, and reaction temperature play a pivotal role in tuning the reactivity of intermediates and controlling the relative rates of competing processes. The novel arylation step is catalyzed by a Pd(OAc)2/NIXANTPHOS-based system via a deprotonative cross-coupling process. The method provides rapid access to skeletally diverse aryl(pyridyl)methanol core structures, which are central components of several medications.
- Gao, Feng,Kim, Byeong-Seon,Walsh, Patrick J.
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p. 976 - 983
(2016/02/05)
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- [1,2]-Wittig rearrangement of aromatic heterocycles
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Anionic rearrangement of diverse heteroaryl ethers is reported. In many cases, directed metallation followed by formal [1,2]-Wittig rearrangement provides heteroaryl carbinols in good yield.
- Yang, Jingyue,Wangweerawong, Apiwat,Dudley, Gregory B.
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scheme or table
p. 1603 - 1606
(2012/08/29)
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- Pyridine-directed organolithium addition to an enol ether
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A previously reported anionic rearrangement of benzyl 2-pyridyl ethers can now be accessed by a distinct and unusual mechanism: addition of alkyllithium reagents to α-(2-pyridyloxy)-styrene triggers an anionic rearrangement to afford tertiary pyridyl carbinols. The process is explained by invoking a contra-electronic, pyridine-directed carbolithiation of the enol ether π-system. Copyright
- Yang, Jingyue,Dudley, Gregory B.
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supporting information; experimental part
p. 3438 - 3442
(2011/02/24)
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- [1,2]-Anionic rearrangement of 2-benzyloxypyridine and related pyridyl ethers
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(Chemical Equation Presented) An anionic rearrangement of 2-benzyloxypyridine is described. Pyridine-directed metalation of the benzylic carbon leads to 1,2-migration of pyridine via a postulated associative mechanism (addition/elimination). Several aryl pyridyl carbinols were obtained in high yields. A formal synthesis of carbinoxamine, an antihistamine drug used for the treatment of seasonal allergies and hay fever, emerges from this methodology.
- Yang, Jingyue,Dudley, Gregory B.
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supporting information; experimental part
p. 7998 - 8000
(2010/03/01)
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