Asymmetric Synthesis of 2-Alkyl-Substituted 2,5-Dihydropyrroles from Optically Active Aza-Baylis−Hillman Adducts. Formal Synthesis of (−)-Trachelanthamidine.
作者:Shingo Ishikawa、Fumiaki Noguchi、Akio Kamimura
DOI:10.1021/jo100315j
日期:2010.6.4
the corresponding 2,3-disubstituted pyrrolidine in good yield. The stereoselectivity of the hydrogenation was sensitive to the presence or absence of the protective group in the C2-side chain. The TBS-protected 2,5-dihydropyrrole gave a 1:1 mixture of the cis/trans isomers, while free alcohol afforded the trans-2,3-disubstituted pyrrolidine in a selectivity of 6:1. The formal synthesis of (−)-trachelanthamidine
Preparation of 2,3-trans-substituted piperidines from optically active β-amino-α-methylene esters: Synthesis of optically active (2S,3R)-(−)-epi-CP-99,994
作者:Akio Kamimura、Ryuichiro Yo、Hidemitsu Uno
DOI:10.1016/j.tet.2017.06.054
日期:2017.8
6-tetrahydropyridine intermediates took place smoothly in the presence of a Pd/C catalyst to give trans-2,3-disubstituted piperidines in good yields and in a highly stereoselective manner. The total synthesis of opticallyactive (2S,3R)-(−)-epi-CP-99,994 was achieved in six-steps from an unsaturated piperidine.
The intramolecularPauson–Khandreaction of aza-Baylis–Hillman adducts, which were prepared through the thio-Michael/imino-aldol domino reaction of optically active sulfinimines, was examined and gave optically active cis- and trans-pyrrolidine-fused cyclopentenones in a stereoselective manner.