80816-23-5Relevant academic research and scientific papers
ALIPHATIC CLAISEN REARRANGEMENT PROMOTED BY ORGANOALUMINIUM REAGENTS.
Takai,Mori,Oshima,Nozaki
, p. 446 - 451 (1984)
Organoaluminium compounds, R//3Al, promote the Claisen rearrangement of allyl vinyl ether derivatives at room temperature under transfer of R or H as a nucleophile to the aldehydic carbon. Treatment of 1-butyl-2-propenyl vinyl ether with a hexane solution of Me//3Al (1. 0 M, 2. 2 equiv) in CH//2ClCH//2Cl at 25 degree C afforded 5-decen-2-ol (91% yield, E/Z equals 47/53), which was produced by the left bracket 3,3 right bracket sigmatropic rearrangement and successive methylation. The rearrangements with alkynylation, alkenylation, and hydrogenation are also achieved. The regular Claisen rearrangement products, of gamma , delta -unsaturated aldehydes (ketones), are obtained at 25 degree C in good to excellent yields with Et//2AlSPh (2. 5 equiv) or the combination of Et//2AlCl (2. 0 euiv) and PPh//3 (2. 2 equiv).
Highly regioselective [3,3] rearrangement of aliphatic allyl vinyl ethers catalyzed by a metalloporphyrin complex, Cr(TPP)Cl
Takanami, Toshikatsu,Hayashi, Mikiko,Iso, Kazuhiro,Nakamoto, Hirose,Suda, Kohji
, p. 9467 - 9474 (2007/10/03)
The Claisen rearrangement of simple aliphatic allyl vinyl ethers catalyzed by a metalloporphyrin, Cr(TPP)Cl, is described. The porphyrin-based Lewis acid catalyst can effectively accelerate the rearrangement via a concerted [3,3] pathway with a minimal degree of bond ionization of the substrates, providing the corresponding Claisen products in moderate to high yields and almost perfect regioselectivity at low catalyst loading.
Organoaluiminum-promoted claisen rearrangement of allyl vinyl ethers
Nonshita, Katsumasa,Banno, Hiroshi,Maruoka, Keiji,Yamamoto, Hishashi
, p. 316 - 322 (2007/10/02)
Unprecedentad stereochemical control has achieved in the Claisen of allyl vinyl of type 4 with certain bulky organoaluminum Thus, methylaluminum bis(4-bromo-2,6-di-tert-butylphenoxide) (reagent A) can be utilized for obtaining the (Z) isomer, (Z)-6, whereas the (E) isomer, (E)-6 was produced with methylaluminum bis(2,6-diphenylphenoxide) (reagent B). This organoaluminum-promoted Claisen rearrangement proceeds under very mild conditions with very good E and Z selectlvities. On the basis of the Claisen rearrangement of optically active substrate 7 with reagent A, the Z selectivity would be interpreted by the intervention of the chairlike transition-state conformation with the isobutyl substituent axial. The present organoalunminum-promoted Claisen rearrangement has successfully applied to the synthesis of (4E,7Z)-4,7-tridecadienyl acetate (15), a component of the sex of tuberworm moth, in stereoselective fashion. Furthermore, the Claisen rearrangement of bisallyl vinyi ether16 with reagent A or B has been found to involve the more substituted allylic system to furnish dienal 18 preferentially, not obtainable in the ordinary thermal rearrangement. This chemistry been further extended to the ionic rearrangement of dienyl vinyl ether 28 by using reagent A in a polar solvent the previously unknown, remote transfer of the vinyloxy moiety by [3,5]-sigmatropic rearrangement via ionic intermediate 29 has observed.
