- Sequential O-Arylation/Lanthanide(III)-Catalyzed [3,3]-Sigmatropic Rearrangement of Bromo-Substituted Allylic Alcohols
-
Lanthanide(III)-catalyzed aryl-Claisen rearrangement of substrates bearing halo-substituted allyl groups, specifically 2-bromoallyl aryl ethers, afford ortho -2-bromoallylphenols. Aryl ether substrates were synthesized from brominated allylic alcohols via Mitsunobu reaction, Cu(II)-catalyzed arylation using potassium aryltrifluoroborate salts, or S N Ar reaction. Aryl-Claisen rearrangements proceeded in moderate to excellent yields using Eu(III) catalysis. The alkenylbromide functionality remains intact, illustrating the compatibility of synthetically important alkenylhalides during C-O/C-C σ-bond migration processes. Subsequent derivatization of the ortho -2-bromoallylphenol products through O-alkylation or C-arylation/alkenylation via Suzuki-Miyaura cross-coupling demonstrate the potential to access densely-functionalized molecules.
- Ramadhar, Timothy R.,Kawakami, Jun-Ichi,Batey, Robert A.
-
supporting information
p. 2865 - 2870
(2017/12/14)
-
- Syntheses of strychnine, norfluorocurarine, dehydrodesacetylretuline, and valparicine enabled by intramolecular cycloadditions of Zincke aldehydes
-
A full account of the development of the base-mediated intramolecular Diels-Alder cycloadditions of tryptamine-derived Zincke aldehydes is described. This important complexity-generating transformation provides the tetracyclic core of many indole monoterpene alkaloids in only three steps from commercially available starting materials and played a key role in short syntheses of norfluorocurarine (five steps), dehydrodesacetylretuline (six steps), valparicine (seven steps), and strychnine (six steps). Reasonable mechanistic possibilities for this reaction, a surprisingly facile dimerization of the products, and an unexpected cycloreversion to regenerate Zincke aldehydes under specific conditions are also discussed.
- Martin, David B. C.,Nguyen, Lucas Q.,Vanderwal, Christopher D.
-
experimental part
p. 17 - 46
(2012/02/04)
-
- New observations in organozinc chemistry: Control of relative stereochemistry in reactions of silicon substituted alkenylzinc reagents
-
Reagents have been synthesised that behave as both Lewis acids and nucleophiles. Reaction of these reagents with electrophiles has led to the finding that diastereoselectivity is observed upon addition to aldehydes. An ordered transition state to account
- Viseux,Parsons,Pavey
-
p. 861 - 863
(2007/10/03)
-
- Studies towards total synthesis of antillatoxin: Investigation of the indium-mediated allylation reactions of carbonyl compounds with β-bromocrotylbromide in water
-
Indium mediates the coupling of β-bromocrotylbromide with carbonyl compounds in saturated ammonium chloride in the presence of lanthanide triflate under sonication to give the corresponding compounds in good yield and moderate to high syn diastereoselecti
- Loh, Teck-Peng,Cao, Guo-Qiang,Pei, Jian
-
p. 1453 - 1456
(2007/10/03)
-
- A new synthesis of indoles
-
Aryl radical cyclisation onto appropriate vinyl bromides leads to a new route to indoles.
- Murphy, John A.,Scott, Karen A.,Sinclair, Rhona S.,Lewis, Norman
-
p. 7295 - 7298
(2007/10/03)
-