- 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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- A PROCESS FOR PREPARATION OF E-ISOMER OF 1-(4-METHYLPHENYL)- 1-(2-PYRID YL)-3-PYRROLIDINO PROP-1-ENE AND ACID ADDITION SALTS THEREOF
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A process for preparation of E-isomer of 1-(4-methylphenyl)-1-(2-pyridyl)-3- pyrrolidinoprop-1-ene of Formula-I, and acid addition salts thereof, said process comprising; dehydrating 1-(4-methylphenyl)-l -(2-pyridyl)-3-pyrrolidinopropan-1-ol of Formula III followed by adding a base solution to obtain a mixture of E and Z isomers of 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene, and washing said mixture of E and Z isomers of 1-(4-methylphenyl)-1-(2-pyridyl)-3- pyrrolidinoprop-1-ene with water to dissolve Z isomer and to obtain E-isomer of 1- (4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene of Formula I, which is substantially free from Z isomer.
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Page/Page column 5; 9
(2009/08/14)
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