Amino acids as precursors to indolizidine alkaloids
作者:Mukund P. Sibi、James W. Christensen
DOI:10.1016/s0040-4039(00)97933-4
日期:1990.1
Enantiocontrolled synthesis of indolizidine alkaloids δ-coniceine [(−)-(R)-octahydroindolizine] and (+)-(1S, 8aS)-1-hydroxyindolizidine, the biosynthetic precursor of slaframine, have been achieved through a condensation of L-prolinal and 3R,2S-hydroxyprolinal, respectively, with a 3-carbon synthon.
Stereochemistry of remote dianion addition to imines. Application to the synthesis of (1S, 8aS)-1-hydroxyindolizidine
作者:Diana L.C. Green、James J. Kiddle、Charles M. Thompson
DOI:10.1016/0040-4020(95)00037-9
日期:1995.3
A stereoselective route to (1S, 8aS)-1-hydroxyindolizidine is reported herein that incorporates as a pivotal step the diastereoselective addition of the dianion of 4-(phenylsulfonyl)butanoic acid (4-PSBA) to a chiral α-benzyloxymethyl imine.
Synthesis and configurational assignment of optically active 1-hydroxyindolizidines
作者:Constance M. Harris、Thomas M. Harris
DOI:10.1016/s0040-4039(00)96147-1
日期:1987.1
The four diastereomers of 1-hydroxyindolizidine have been prepared in high optical purity (>98%) by NaBH4 reduction of the (+) and (-) 3-bromocamphor-8-sulfonic acid salts of 1-oxoindolizidine followed by separation of the resulting diastereomeric alcohols by ion-exchange chromatography.
A highly stereoselective approach to 1-hydroxyindolizidine is described using a Grignard reaction on N-benzyl imine derived from 3-deoxy-1,2-O-isopropylidine-alpha-D-xylo-pentodialdofuranose and reductive cyclization as key steps. (C) 2010 Elsevier Ltd. All rights reserved.
Enantiospecific Synthesis of (−)-Slaframine and Related Hydroxylated Indolizidines. Utilization of a Nucleophilic Alaninol Synthon Derived from Serine<sup>1</sup>
作者:Mukund P. Sibi、James W. Christensen
DOI:10.1021/jo9908546
日期:1999.8.1
A general methodology for the synthesis of indolizidine alkaloids delta-coniceine (12), 1-hydroxyindolizidine (20), desacetoxy slaframine (24), slaframine (34), and an analogue (37) has been developed. This convergent approach utilizes the available chirality in proline and serine and is conceptually different from other approaches. A highly stereoselective coupling of the prolinals with a nucleophilic alaninol synthon provides the precursors for the key cyclization. A novel thermolytic annulation of an oxazolidinone is the key step in the formation of the six-membered piperidine ring. Further elaboration provides the target natural products 24, 34, and 37 in good overall yields.