Asymmetric Construction of a Quaternary Carbon Center by Tandem [4 + 2]/[3 + 2] Cycloaddition of a Nitroalkene. The Total Synthesis of (−)-Mesembrine

1997 ◽  
Vol 62 (6) ◽  
pp. 1675-1686 ◽  
Author(s):  
Scott E. Denmark ◽  
Lawrence R. Marcin
Keyword(s):  
Total Synthesis ◽  
Quaternary Carbon

scholarly journals Recent development and applications of semipinacol rearrangement reactions

2021 ◽  
Author(s):  
Xiao-Ming Zhang ◽  
Bao-Sheng Li ◽  
Shao-Hua Wang ◽  
Kun Zhang ◽  
Fu-Min Zhang ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Quaternary Carbon ◽  
Carbon Formation ◽  
Semipinacol Rearrangement ◽  
Rearrangement Reactions

The recent development of semipinacol rearrangement is reviewed, highlighting its application in β-functionalized ketone synthesis, quaternary carbon formation and total synthesis.

d- and l-Erythrose as sources of chiral quaternary carbon centers. Total synthesis of (−)-malyngolide and (+)-tanikolide

2003 ◽  
Vol 44 (12) ◽  
pp. 2513-2516 ◽  
Author(s):  
Alexandros E. Koumbis ◽  
Kyriaki M. Dieti ◽  
Myrofora G. Vikentiou ◽  
John K. Gallos
Keyword(s):  
Total Synthesis ◽  
Quaternary Carbon ◽  
Carbon Centers

Kinetic resolution of oxime esters with lipases — synthesis of enantiomerically enriched building blocks with quaternary carbon centers and formal total synthesis of perhydro histrionicotoxin

2002 ◽  
Vol 80 (6) ◽  
pp. 686-691 ◽  
Author(s):  
Nicole Diedrichs ◽  
Ralf Krelaus ◽  
Ina Gedrath ◽  
Bernhard Westermann
Keyword(s):  
Substrate Specificity ◽  
Total Synthesis ◽  
Solvent Effects ◽  
Kinetic Resolution ◽  
Building Blocks ◽  
Beckmann Rearrangement ◽  
Optically Active ◽  
Quaternary Carbon ◽  
Carbon Centers

Enantiomerically enriched oximes bearing stereogenic quaternary carbon centers can be obtained by lipase-catalyzed kinetic resolution of oxime esters. Substrate specificity, solvent effects, and the use of different lipases are discussed. Kinetic resolution of butyrylated oximes by lipase PS in the presence of n-butanol gave the best ee-values of both the saponified oxime and the residual oxime ester. Subsequent stereospecific Beckmann rearrangement of an enantiomerically enriched oxime provided lactams, which could be employed for the synthesis of optically active perhydro histrionicotoxin.Key words: oxime, lipase, kinetic resolution, Beckmann rearrangement, perhydro histrionicotoxin.

Construction of an asymmetric quaternary carbon via an asymmetric aza-Claisen rearrangement and its application in the total synthesis of (+)-α-cuparenone

2012 ◽  
Vol 23 (10) ◽  
pp. 739-741 ◽  
Author(s):  
Takeshi Nishii ◽  
Fumiaki Miyamae ◽  
Makoto Yoshizuka ◽  
Hiroto Kaku ◽  
Mitsuyo Horikawa ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Claisen Rearrangement ◽  
Quaternary Carbon

scholarly journals The Theoretical Total Synthesis of an Aromatic Esters of the Crinane Amaryllidaceae Alkaloid Ambelline

2021 ◽  
Vol 267 ◽  
pp. 02011
Author(s):  
Danyang Liu ◽  
Zhijian Zhou ◽  
Hao Liu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Total Synthesis ◽  
Weak Acid ◽  
Alder Reaction ◽  
Diels Alder ◽  
Quaternary Carbon ◽  
Aromatic Esters ◽  
Diels Alder Reaction ◽  
Theoretical Synthesis

ABSTRACT. A series of crinane-type alkaloid ambelline derivatives were assessed for their potency to inhibit both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), which has been shown to be effective medicine for the treatment of Alzheimer’s disease. However, no enzyme modification has been reported total synthesis. In this work, two possible theoretical synthesis paths of Crinane-type alkaloid ambelline were discussed in this article. The major difficulty of the proposed synthesis was the synthesis of the quaternary carbon. One of the approaches emphasized on the reactions between cyclic and heterocyclic compounds and substrates on the intermediates to generate the quaternary carbon shown on the desired product. The other approach utilized series of amine reactions and Michael addition to create the precursor for the reactant in the Diels-Alder reaction and, therefore, the quaternary carbon, and finally, the desired natural product was obtained after a weak acid workup. The synthesis of ambelline has the potential to provide new pathways for treatment of Alzheimer’s disease.

scholarly journals Synthesis of Cyclohexane-Angularly-Fused Triquinanes

Synthesis ◽  
2020 ◽  
Author(s):  
Hongjun Jeon ◽  
Jeffrey D. Winkler
Keyword(s):  
Total Synthesis ◽  
Synthetic Approach ◽  
Quaternary Carbon ◽  
Carbon Centers ◽  
Naturally Occurring

AbstractCyclohexane-angularly-fused triquinanes, 6-5-5-5 tetra­cycles, have attracted the attention of synthetic chemists due to their highly congested core structures and multiple quaternary carbon centers. This review focuses on the six completed total synthesis of naturally occurring cyclohexane-angularly-fused triquinanes in addition to seven notable methodologies that have been developed for the synthesis of these structures.1 Introduction2 6-5-5-5 Tetracycles Containing a Linear Triquinane2.1 Total Synthesis of Cyclopiane Diterpenes2.2 Synthetic Approach toward Aberrarane Diterpenes2.3 Intermediates in the Total Synthesis of Magellanine-Type Alkaloids3 6-5-5-5 Tetracycles Containing an Angular Triquinane3.1 Total Synthesis of Waihoensene3.2 Miscellaneous Approaches4 Conclusion

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