Transition-Metal-Mediated Cascade Reactions: The Water-Accelerated Carboalumination−Claisen Rearrangement−Carbonyl Addition Reaction
作者:Peter Wipf、David L. Waller、Jonathan T. Reeves
DOI:10.1021/jo051211v
日期:2005.9.1
water-accelerated catalytic carboalumination, a Claisen rearrangement, and a nucleophilic carbonyl addition converts terminal alkynes and allyl vinyl ethers into allylic alcohols containing up to three contiguous asymmetric carbon centers. Stoichiometric quantities of water as an additive increase the rate of the [3,3] sigmatropicrearrangement as well as the diastereoselectivity of the carbonyl addition
Iminyl radicals: Part I. generation and intramolecular capture by an olefin.
作者:Jean Boivin、Eric Fouquet、Samir Z. Zard
DOI:10.1016/s0040-4020(01)80849-8
日期:1994.1
Slow addition of tributylstannane to sulphenylimines 2 give the corresponding Δ1- pyrrolenines 5 by an intramolecularaddition of the intermediate iminyl radical, a process which can be easily coupled to an intermolecular addition to an electrophilic olefin.
Tandem Diels−Alder Cycloadditions of 2-Pyrone-5-acrylates for the Efficient Synthesis of Novel Tetracyclolactones
作者:Soo-Im Chung、Joobeom Seo、Cheon-Gyu Cho
DOI:10.1021/jo061119e
日期:2006.8.1
Readily prepared from the regioselective Pd-catalyzed coupling reactions of 3,5-dibromo-2-pyrone, 3-bromo-2-pyrone-5-carboxylates undergo tandem uninterrupted sequential Diels−Aldercycloaddition reactions with allyl vinyl ethers in a highly regio- and stereoselective fashion to provide a series of novel tetracyclolactones in good yields.
Highly regioselective [3,3] rearrangement of aliphatic allyl vinyl ethers catalyzed by a metalloporphyrin complex, Cr(TPP)Cl
作者:Toshikatsu Takanami、Mikiko Hayashi、Kazuhiro Iso、Hirose Nakamoto、Kohji Suda
DOI:10.1016/j.tet.2006.07.051
日期:2006.10
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
(2,7-Disubstituted-1,8-biphenylenedioxy)bis(dimethylaluminum) as Bidentate Organoaluminum Lewis Acids: Elucidation and Synthetic Utility of the Double Electrophilic Activation Phenomenon
temperature; this primarily relies on the successful establishment of a new synthetic procedure of 1 starting from inexpensive m-anisidine. Evaluation of 2 as a bidentate organoaluminum Lewisacid has been performed by the reduction of ketonic substrates using Bu3SnH as a hydride source in comparison to the conventional monodentate Lewisacid dimethylaluminum 2,6-xylenoxide (11), uncovering the significantly