- Synthesis of cis-3,4-diarylpiperidines and cis-3,4-diaryltetrahydropyrans
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Substituted cis-3,4-diarylpiperidines and cis-3,4-diaryltetrahydropyrans are synthesized in modest overall yields starting from 4-aryl-1,2,5,6-tetrahydropyridines and 4-aryl-1,2,5,6-tetrahydropyrans via the following sequence: (1) pinacol-type ring contraction having the?combination of m-chloroperoxybenzoic acid and boron trifluoride etherate, (2) Grignard addition with arylmagnesium bromide reagents and followed by boron trifluoride etherate-mediated intramolecular ring-expanded rearrangement, and (3) hydrogenation with hydrogen on 10% palladium-activated carbon. A facile synthesis of 3,4-diarylpyridines was also described by base-induced aromatization.
- Chang, Meng-Yang,Lin, Chun-Yu,Hung, Ching-Yi
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p. 3312 - 3320
(2007/10/03)
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- New synthesis of 3-arylpyrrolines
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We present an easy and straightforward synthesis of 3-arylpyrrolines 4a-g by repeated treatment of 4-aryl-1,2,5,6-tetrahydropyridines 2a-g with m-chloroperoxybenzoic acid (MCPBA) and boron trifluoride etherate (BF 3-OEt2). The transformation proceeds via epoxidation, ring contraction, Baeyer-Villiger oxidation and elimination reaction and affords 3-arylpyrrolines 4a-g with 61-70% yield. This facile strategy was also used to synthesize racemic baclofen (6).
- Chang, Meng-Yang,Pai, Chun-Li,Kung, Yung-Hua
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p. 855 - 859
(2007/10/03)
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