Chiral 1,4-dihydropyridine equivalents: a new approach to the asymmetric synthesis of alkaloids. The enantiospecific synthesis of (+)- and (-)-coniine and dihydropinidine

Natural Tetraponerines: A General Synthesis and Antiproliferative Activity

“…13 The group of Royer applied its CN (R,S) strategy 14 to the synthesis of all natural tetraponerines known, being the only general method reported to prepare this entire family of alkaloids up to date. 15 Aware of the lack of detailed structural information of tetraponerines we have recently examined the conformational and configurational space of T3 and T4.…”

Alkylation studies of a polyhydroxylated-cyano-piperidine scaffold

“…Our purpose is to compare the reactivity of our building block 1 with regard to the CN(R,S) synthon created by Husson's group (Scheme 2), under the same experimental conditions. 28 Following the literature data, 29 we studied the methylation of 1 with iodomethane at -78 °C in THF in presence of lithium diisopropylamine. First attempts were carried out on compound 1 without success.…”

Enantioselective Syntheses and Absolute Configuration of the Ladybird Defence Alkaloids (+)-Calvine and (+)-2-Epicalvine

“…The observed stereoselectivity is interpreted in terms of an elimination-addition mechanism in which the hydride ion approaches a preferred iminium conformer from an axial direction, under complete stereoelectronic control. [13] The chiral appendage of (2S)-4 was then removed under catalytic hydrogenolysis conditions (H 2 , 10% Pd/C, MeOH) to afford piperidine (2S)-5 in nearly quantitative yield. Protection of the secondary amine of (2S)-5 with methyl chloroformate led to the carbamate (2S)-6 in 84% yield and Ͼ 99% ee.…”