184535-05-5Relevant academic research and scientific papers
Concise total synthesis and stereochemical analysis of tetraponerines T3 and T4
Bosque, Irene,Gonzalez-Gomez, Jose C.,Guijarro, Albert,Foubelo, Francisco,Yus, Miguel
, p. 10340 - 10346 (2013/01/15)
An efficient stereocontrolled preparation of tetraponerines T3 and T4 is detailed. The sequence takes advantage of two consecutive stereoselective aminoallylations of appropriate aldehydes with chiral tert-butanesulfinamide and in situ generated allyl indium species. The absolute configuration of the carbon stereogenic center at the aminal moiety is thermodynamically controlled. This was ascertained on the basis of an exhaustive DFT configurational study of tetraponerines, which fulfils the lack of detailed structural information for these systems. It was found that the trans-transoid-configuration of the AB rings is the most stable geometry for T3 and T4. However, the C ring prefers a cis-configuration in T3 (ttc-T3) and a trans-fusion in T4 (ttt-T4). Regarding their dynamic behavior, low activation barriers were found by DFT calculations for the inversion of the nitrogen at the indolizidine framework, allowing rapid equilibration between the major configurations (ttc and ttt) in T3 and T4.
Enantioselective organocatalytic intramolecular aza-Michael reaction: A concise synthesis of (+)-sedamine, (+)-allosedamine, and (+)-coniine
Fustero, Santos,Jimenez, Diego,Moscardo, Javier,Catalan, Silvia,Del Pozo, Carlos
, p. 5283 - 5286 (2008/09/18)
(Chemical Equation Presented) The intramolecular aza-Michael reaction of carbamates bearing remote α,β-unsaturated aldehydes under organocatalytic conditions took place with good yields and excellent ee's when Jorgensen catalyst IV was used in the process, giving rise to the enantioselective formation of several five- and six-membered heterocycles. The developed methodology was applied to the synthesis of three piperidine alkaloids.
A new asymmetric entry to 2-substituted piperidines. A concise synthesis of (+)-coniine, (-)-pelletierine, (+)-δ-coniceine, and (+)-epidihydropinidine
Takahata, Hiroki,Kubota, Minoru,Takahashi, Seiki,Momose, Takefumi
, p. 3047 - 3054 (2007/10/03)
A new asymmetric route to 2-substituted piperidines involving the Sharpless asymmetric dihydroxylation (AD) of 5-hexenylazide 1 and an intramolecular aminocyclization as crucial steps and its application to the asymmetric synthesis of four piperidine alkaloids, (+)-coniine 2, (-)-pelletierine 3, (+)-δ-coniceine 4, aND (+)-epidihydropinidine 5 is presented.
Diastereofacial Selectivity in Intermolecular Nitrone Cycloadditions to Chiral Allyl Ethers. Application to Chiral Synthesis of Coniine
Ito, Masayuki,Maeda, Masae,Kibayashi, Chihiro
, p. 3765 - 3768 (2007/10/02)
The intermolecular cycloadditions of a cyclic nitrone to chiral allyl ethers take place with erythro selectivity, where the degree of selectivity achieved is dependent upon the size of the alkyl substituent attached to the allylic chiral center, and these reactions are applied to the synthesis of optically active alkaloid coniine.
