Synthetic Studies of Alkaloids Containing Pyrrolidine and Piperidine Structural Motifs
作者:Chinmay Bhat
DOI:10.1002/open.201402128
日期:2015.4
Avenues to asymmetricalkaloids! Various 2‐substituted pyrrolidine and piperidine chiral bioactive natural products were synthesized using a ‘chiral pool’ method. l‐proline and l‐pipecolinic acids with one chiral center served as the best precursors for the synthesis of these alkaloids. Overall, 14 total synthetic and 11 formal synthetic approaches were developed.
New synthesis of all the four isomers of 2-(2-hydroxypropyl)pyrrolidines via iterative asymmetric dihydroxylation to cause enantiomeric enhancement
作者:Hiroki Takahata、Minoru Kubota、Takefumi Momose
DOI:10.1016/s0957-4166(97)00348-0
日期:1997.8
Both enantiomers of 2-(2-propenyl)pyrrolidine 7 (75–84% ee), prepared via the asymmetricdihydroxylation (AD) of terminal olefin 5, underwent the second AD to provide all of the four stereoisomeric 2-(2-hydroxypropyl)pyrrolidines 8 with enantiomeric enhancement (>98% ee). An asymmetricsynthesis, starting from 8, of several 2-(2-hydroxypropyl)pyrrolidine alkaloids is demonstrated.
Synthesis of (−)-hygrine, (−)-norhygrine, (−)-pseudohygroline and (−)-hygroline via Nef reaction
作者:Chinmay Bhat、Santosh G. Tilve
DOI:10.1016/j.tetlet.2011.09.118
日期:2011.12
Synthesis of tropane alkaloids (-)-hygrine, (-)-norhygrine and sedum alkaloids (-)-pseudohygroline and (-)-hygroline is described from L-proline via Henry and Nef reactions. (C) 2011 Elsevier Ltd. All rights reserved.
Total Synthesis of Hygrolines and Pseudohygrolines
A concise two-step synthesis of all four diastereoisomeric hygrolines ((-)-hygroline (1), (+)-hygroline (2), (-)-pseudohygroline (3), (+)-pseudohygroline (4)) has been developed based on the (-)-sparteine (5)- or (+)-sparteine surrogate 11-mediated enantioselective lithiation of N-Boc pyrrolidine (6), followed by reaction of the chiral anion with (S)- or (R)-propylene oxide. Reduction of the resulting N-Boc amino alcohols furnished hygrolines and pseudohygrolines in 30% to 56% overall yields with dr's > 95:5.