Asymmetric Robinson Annulation

2015 ◽  
pp. 54-59
Keyword(s):  
Robinson Annulation

An Overview on the Robinson Annulation

2018 ◽  
Vol 22 (14) ◽  
pp. 1347-1372 ◽  
Author(s):  
Zai-Qun Liu
Keyword(s):  
Robinson Annulation

A modified Robinson annulation process to α,α-disubstituted-β,γ-unsaturated cyclohexanone system. Application to the total synthesis of nanaimoal

Tetrahedron ◽  
2003 ◽  
Vol 59 (8) ◽  
pp. 1209-1226 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Tai Wei Ly ◽  
Chia-Liang Tai ◽  
Jen-Dar Wu ◽  
Jinn-Kwei Liang ◽  
...  
Keyword(s):  
Total Synthesis ◽  
System Application ◽  
Robinson Annulation

Robinson Annulation-Directed Synthesis of Jet-Fuel-Ranged Alkylcyclohexanes from Biomass-Derived Chemicals

ACS Catalysis ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 3280-3285 ◽  
Author(s):  
Yaxuan Jing ◽  
Qineng Xia ◽  
Junjian Xie ◽  
Xiaohui Liu ◽  
Yong Guo ◽  
...  
Keyword(s):  
Jet Fuel ◽  
Directed Synthesis ◽  
Robinson Annulation

Robinson annulation

2003 ◽  
pp. 340-340
Author(s):  
Jie Jack Li
Keyword(s):  
Robinson Annulation

The Toste Synthesis of ( + )-Fawcettimine

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Current Method ◽  
Conjugate Addition ◽  
Enantioselective Synthesis ◽  
University Of California ◽  
Lycopodium Alkaloid ◽  
Silyl Enol Ether ◽  
Terminal Alkene ◽  
Robinson Annulation ◽  
The University ◽  
Stereogenic Center

The tetracyclic Lycopodium alkaloid fawcettimine 3 and its derivatives are of interest as inhibitors of acetylcholine esterase. F. Dean Toste of the University of California, Berkeley recently reported (Angew. Chem. Int. Ed. 2007, 46, 7671) the first enantioselective synthesis of 3. The key to the synthesis was the rapid assembly of the enantiomerically-enriched hydrindane 2. The preparation of 2 began with the enantioselective Robinson annulation of the β-keto ester 4 with crotonaldehyde 5, mediated by the organocatalyst 6. In this protocol, originally developed by Karl Anker Jørgensen, the single stereogenic center was established by conjugate addition, presumably to the chiral iminium salt generated by the condensation of 5 with 6. Subsequent aldol (or more likely Mannich) cyclization followed by elimination gave 7. Hydrolysis and decarboxylation by heating with p-TsOH converted 7 to 1. This procedure was robust enough to allow preparation of a ten gram batch of 1. This Jørgensen annulation is the current method of choice for the enantioselective preparation of 2,5-dialkyl cyclohexenones. Conjugate addition of the propargyl anion equivalent 8 to 1 proceeded with the expected > 95:5 axial diastereoselectivity, to give the silyl enol ether 9. Exposure of the derived iodide 10 to catalytic [Ph3 PAu]Cl and AgBF4 induced smooth cyclization to the cis hydrindane 2. Before constructing the nine-membered ring amine of fawcettimine 3, it was first necessary to protect the ketone as the ketal. Pd-mediated coupling of the alkenyl iodide with the organoborane derived from 11 then proceeded smoothly, as did the subsequent hydroboration of the terminal alkene. Neither the mesylate nor the tosylate derived from 12 could be induced to cyclize. In contrast, intramolecular displacement of the iodide proceeded well, to give 13. Hydroboration followed by oxidation then gave 15, which on deprotection cyclized to (+)-fawcettimine 3. Several aspects of this synthesis are attractive. While the stereochemical outcome of the hydroboration of 14 could not necessarily be predicted with confidence, in fact it did not matter, as the stereogenic center adjacent to the ketone could be epimerized under the trifluoroacetic acid deprotection conditions, and only the desired diastereomer would be able to add in an intramolecular fashion to the cyclohexanone.

scholarly journals Enantioselective Synthesis of the ABC Ring Motif of Norzoanthamine Based on Asymmetric Robinson Annulation Reactions

2011 ◽  
Vol 13 (13) ◽  
pp. 3308-3311 ◽  
Author(s):  
Thong X. Nguyen ◽  
Marianna Dakanali ◽  
Lynnie Trzoss ◽  
Emmanuel A. Theodorakis
Keyword(s):  
Enantioselective Synthesis ◽  
Robinson Annulation ◽  
Ring Motif

Organotin triflates as functional lewis acids. A new entry to simple and efficient robinson annulation

1990 ◽  
Vol 31 (11) ◽  
pp. 1581-1584 ◽  
Author(s):  
Tsuneo Sato ◽  
Yoshiyuki Wakahara ◽  
Junzo Otera ◽  
Hitosi Nozaki
Keyword(s):  
Lewis Acids ◽  
Robinson Annulation ◽  
New Entry

Structure of a by-product formed during use of the Robinson annulation reaction with 6-methoxy-1-methyl-2-tetralone

1981 ◽  
Vol 46 (8) ◽  
pp. 1755-1757 ◽  
Author(s):  
Ajoy K. Banerjee ◽  
Magaly S. Rizo ◽  
Miguel E. Alonso ◽  
Anibal Rojas ◽  
John L. Haack ◽  
...  
Keyword(s):  
Robinson Annulation

ChemInform Abstract: Base-Promoted Reactions in Ionic Liquid Solvents. The Knoevenagel and Robinson Annulation Reactions.

ChemInform ◽  
2010 ◽  
Vol 33 (2) ◽  
pp. no-no
Author(s):  
Doug W. Morrison ◽  
David C. Forbes ◽  
James H. Davis Jr.
Keyword(s):  
Ionic Liquid ◽  
Robinson Annulation
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