Reactions of some alkynyl halides with Samarium(II) iodide
作者:Zhihong Zhou、Denis Larouche、Sharon M. Bennett
DOI:10.1016/0040-4020(95)00703-b
日期:1995.10
Certain alkynyl halides (6-halo-1-ynes) react with samarium(II) iodide (SmI2) to give cyclized products (methylenecyclopentanes) in good yield. We have found some interesting evidence for the presence of radical and unstable organosamarium intermediates in these reductive cyclizations. Methyl 7-halohept-2-ynoates are not. however, good substrates for this cyclization methodology.
preparation of the piperidine precursors is based on a chain elongation of a piperidine aldehyde either by aldolization or by Wittig reaction. We applied this second route to the total synthesis of quinolizidine (−)-217A from (S)-methyl 2-((S)-1-((R)-1-phenylethyl)piperidin-2-yl)propanoate 5.
A strong base-induced intramolecular cycloaddition reaction homophthalicanhydride has been examined as a method for preparing polycyclic perihydroxy aromatic compounds.
An efficient synthesis of chiral pyrrolidine and piperidine enamino esters is described in one step from methyl halogeno alcynoate and (S)-1-phenylethylamine or (S)-phenylglycinol.
Synthesis of Fused Tricyclic Amines Bearing Tetrasubstituted Carbons Using an Alkylation–Cyclization–Isomerization–3-aza-Cope Cascade Reaction
作者:Takeo Sakai、Tomoki Furuhata、Kota Hosoe、Kaho Umemura、Yuji Mori
DOI:10.1021/acs.orglett.3c00778
日期:2023.5.5
A new cascade reaction sequence that involves alkylation, cyclization, isomerization, and 3-aza-Cope rearrangement was discovered. The stereogenic centers of the starting piperidines were transferred to the bicyclic enamine products, and a range of electron-withdrawing groups on the alkyne moieties, from ketones to amides, were tolerated under the reaction conditions. The bicyclic enamines underwent