Stereoselective Synthesis of (+)-Euphococcinine and (−)-Adaline
摘要:
We describe the syntheses of (+)-euphococcinine and (-)-adaline, two naturally occurring alkaloids containing a quaternary carbon bearing a nitrogen atom. Key features of the syntheses are a 3,3-sigmatropic rearrangement to give an all-carbon quaternary center, a ring-closing alkene metathesis to give an 8-membered ring, and the use of a single enantiomer of p-menthane-3-carboxaldehyde to make two natural alkaloids of opposite configuration.
Assymetric syntheses of the ladybug alkaloid adaline and 1-methyl-9-azabicyclo [3.3.1]nonan-3-one
作者:Richard K. Hill、Louis A. Renbaum
DOI:10.1016/0040-4020(82)80045-8
日期:1982.1
The double Michael addition of benzylamine to 3-alkyl-2,7-cyclooctadienones, followed by hydrogenolysis, affords bridgehead substituted 9-azabicyclo[3.3.1]nonan-3-ones. Use of (+)-α-methylbenzylamine in the addition leads to mixtures of diastereomeric adducts in unequal amounts. Although the degree of asymmetric induction is low (10–20% ee), the diastereonomers can be easily separated, affording pure
An efficient, asymmetric synthesis of (+)-euphococcinine
作者:Mark F Mechelke、A.I Meyers
DOI:10.1016/s0040-4039(00)00665-1
日期:2000.6
The enantioselective synthesis of (+)-euphococcinine (1), a homotropane alkaloid, has been achieved in five steps from bicyclic lactam 5. (C) 2000 Elsevier Science Ltd. All rights reserved.
Synthesis of Homochiral b-Sulfinyl Nitrones and Their Application for Enantioselective Synthesis of (+)-Euphococcinine
Homochiral beta-sulfinyl nitrones can be prepared from secondary amines in three steps. Enantioselective synthesis of defensive alkaloid (+)-euphococcinine (9) has been accomplished by means of diastereoselective allylation of homochiral beta-sulfinyl nitrone (13) followed by intramolecular 1,3-dipolar cycloaddition reaction.
Stereoselective Synthesis of (+)-Euphococcinine and (−)-Adaline
We describe the syntheses of (+)-euphococcinine and (-)-adaline, two naturally occurring alkaloids containing a quaternary carbon bearing a nitrogen atom. Key features of the syntheses are a 3,3-sigmatropic rearrangement to give an all-carbon quaternary center, a ring-closing alkene metathesis to give an 8-membered ring, and the use of a single enantiomer of p-menthane-3-carboxaldehyde to make two natural alkaloids of opposite configuration.
4-Hydroxylated Piperidines and <i>N</i>-Methyleuphococcinine (1-Methyl-3-granatanone) from <i>Picea</i> (Spruce) Species. Identification and Synthesis
作者:Jeanne N. Tawara、Peter Lorenz、Frank R. Stermitz
DOI:10.1021/np9802769
日期:1999.2.1
Three trace alkaloidsfrom Colorado blue spruce, Picea pungens, were identified by synthesis and GC-MS comparisons as 4alpha-hydroxy-cis-2-methyl-6-(2-oxopropyl)piperidine (1), 4alpha-hydroxy-cis-2-methyl-6-propylpiperidine (11), and 1-methylgranatanone (15) (N-methyl-9-aza-1-methylbicyclo[3.3. 1]nonane or N-methyleuphococcinine). Alkaloids 1 and 11 are the first among numerous known pine and spruce