Ketones are reported to be conveniently converted into their α-tolylsulfinylated derivatives. This new procedure is based on the reaction of their corresponding trimethylsilyl enol ethers with p-toluenesulfinyl p-tolylsulfone in the presence of tris(dimethylamino)sulfur trimethylsilyldifluoride (TAS-F). Considering that β-ketosulfoxides are key intermediates for the preparation of α,β-unsaturated ketones
VinylogousMukaiyama‐type aldolreactions have been catalyzed by a combination of Cu(OTf)2 and readily available C1‐symmetric aminosulfoximines. After a fine‐tuning of the reaction conditions and an optimization of the modularly assembled ligand structure, high stereoselectivities and excellent yields have been achieved in catalyzed reactions involving various electrophile/nucleophile combinations
O-Silylated dienolates in organic synthesis: γ-Selective alkylation of unsaturated carbonyl compounds by 1,5-dithienium fluoroborate.
作者:Ian Paterson、Lee G. Price
DOI:10.1016/s0040-4039(01)90565-9
日期:1981.1
The alkylation of O-silylated dienolates of unsaturated aldehydes, ketones, and esters with 1,3-dithienium fluoroborate shows useful γ-selectivity. The γ-products are selectively protected 1,5-dicarbonyl compounds.
An approach to the synthesis of gelsemine: the intramolecular reaction of an allylsilane with an acyliminium ion for the synthesis of one of the quaternary centres
作者:Carol Clarke、Ian Fleming、Joseph M.D. Fortunak、Peter T. Gallagher、Matthew C. Honan、André Mann、Christoph O. Nübling、Paul R. Raithby、J.Jens Wolff
DOI:10.1016/s0040-4020(01)86646-1
日期:1988.1
steps in the synthesis are (i) the Diels-Alder reactionbetween 1-tetrahydropyranyloxycyclohexa-1,3-diene (10) and methyl β-nitroacrylate (11) giving an adduct (12), in which the chiral centre in the tetrahydropyranyl ring is produced substantially in only one sense, (ii) the rearrangement of a bicyclo [2.2.2] octane (23) into a bicyclo[ 3.2.1] octane (24), where control of which bridge migrates is