52358-22-2Relevant academic research and scientific papers
Highly Regioselective α-Addition of Alkynyl and Alkenyl Grignard Reagents to 1-Alkoxycarbonylpyridinium Salts and Its Application to Synthesis of 1-Azabicycloalkanes and (+/-)-Solenopsin A
Yamaguchi, Ryohei,Nakazono, Yutaka,Matsuki, Toshitsugu,Hata, Ei-ichiro,Kawanisi, Mituyosi
, p. 215 - 222 (2007/10/02)
Nucleophilic addition of a variety of alkynyl and alkenyl Grignard reagents to 1-methoxycarbonylpyridinium chloride takes place at the α-position in a highly regioselective manner to give 2-substituted 1-methoxycarbonyl-1,2-dihydropyridines exclusively, while, with alkyl Grignard reagents, a lack of the regioselectivity is observed.These results may be explained by the HSAB principle.The high α-regioselectivity is preserved in the cases of 2-substituted pyridines as well, giving 2,6-disubstituted 1,2-dihydropyridines exclusively, which can be transformed stereoselectively into cis- and trans-2,6-dialkylated piperidines.These highly regioselective α-alkynylations of 1-methoxycarbonylpyridinium salts are exploited in synthesis of 1-azabicycloalkanes as well as (+/-)-solenopsin A.
A NEW METHOD FOR REGIOSELECTIVE SYNTHESIS OF 2-SUBSTITUTED 1-(METHOXYCARBONYL)-1,2-DIHYDROPYRIDINES
Shono, Tatsuya,Matsumura, Yoshihiro,Onomura, Osamu,Yamada, Yasufu
, p. 4073 - 4074 (2007/10/02)
2-Substituted 1,2-dihydropyridines including an optically active one were regioselctively prepared from 2-substituted piperidines through three intermediates, that is, (a) 1,2,3,4-tetrahydropyridines, (b) 5-bromo-6-methoxypiperidines, and (c) 1,2,3,4-tetrahydro-6-methoxypyridines.
ON THE REGIOSELECTIVITY OF THE REACTION OF N-METHOXYCARBONYLPYRIDINIUM CHLORIDE WITH GRIGNARD REAGENTS: HIGHLY REGIOSELECTIVE SYNTHESIS OF 2-SUBSTITUTED N-METHOXYCARBONYL-1,2-DIHYDROPYRIDINES.
Yamaguchi, Ryohei,Nakazono, Yutaka,Kawanisi, Mituyosi
, p. 1801 - 1804 (2007/10/02)
Whereas alkyl Grignard reagents undergo 1,2- and 1,4-additions to N-methoxycarbonyl-pyridinium chloride in a variable ratio, alkenyl and alkynyl Grignard reagents do the exclusive 1,2-addition to afford 2-substituted N-methoxycarbonyl-1,2-dihydropyridines in fair to excellent yields.
STEREOSELECTIVE SYNTHESIS OF dl-PROSAFRININE AND dl-PSEUDOCARPAMIC ACID
Natsume, Mitsutaka,Ogawa, Masashi
, p. 615 - 618 (2007/10/02)
The SnCl2-effected carbon-carbon bond formation of endoperoxides was applied to alkyl substituted 1,2-dihydropyridines 1a-h to produce 3a-h and 4a-h, whose stereochemistry was clarified.Starting from 3e and 4e, piperidine alkaloids, prosafrinine and pseud
