The Au(I)-catalyzed intermolecular hydroalkoxylation of alkynes with allylic alcohols to provide allyl vinyl ethers that subsequently undergo Claisen rearrangement is reported. This new cascade reaction strategy facilitates the direct formation of γ,δ-unsaturated ketones from simple starting materials in a single step.

Homoallenic alcohols are prepared from propargyl vinyl ethers using a trinuclear gold(I)-oxo complex, [(Ph3PAu)3O]BF4, as a catalyst for propargyl Claisen rearrangement at room temperature. The gold(I)-catalyzed reaction is effective for a diverse collection of propargyl vinyl ethers, including substrates containing aryl and alkyl groups at the propargylic position, and hydrogen, aryl, and alky...

The doubly diastereoselective [3,3]-sigmatropic aza-Claisen rearrangement of silylketene aminals derived from 5-substituted (3S,4E,alphaR)-1-benzyloxy-3-[N-acyl-N-(alpha-methylbenzyl)amino]pent-4-enes furnishes 2,3-disubstituted (R)-N-alpha-methylbenzyl (2S,3R,4E)-7-benzyloxyhept-4-enamides in >90% de under the "matched" control of both stereogenic centres. Rearrangement of the "mismatched" dia...

The propargyl Claisen rearrangement is a known protocol to gain access to functionalized allenes through the [3,3]-sigmatropic transformation of propargyl vinyl ethers. The correct use of appropriate propargyl vinyl ethers as starting materials coupled with suitable reaction conditions can aid in the development of new domino methodologies in which the allenes are valuable intermediates in rout...

A series of 3-allenyl benzo[b]thiophenes were synthesized through a gold(I)-catalyzed domino reaction. The process consists in 5-endo-dig cyclization with C−S bond formation and consecutive S-to-C propargyl migration via [3,3]-sigmatropic Claisen rearrangement. With aryl substituents on both triple bonds the substrate, subsequent intramolecular hydroarylation formed allenyl system led to 3-inde...

γ-Aminobutiric acid (GABA), the major inhibitory neurotransmitter in the central nervous system is activated by the antispastic and muscle relaxant agent, Baclofen, which is a lipophilic derivative of GABA. Because of its biological and pharmacological importance, there are several reports in the literature about the synthesis of baclofen since 1962. In this study baclofen was easily synthesize...

In order to construct the functionalized AB ring system of clifednamide, member of the class of macrocyclic tetramic acid lactams, a synthesis was developed which utilized an Ireland-Claisen rearrangement and an intramolecular Diels-Alder reaction. Starting from di-O-isopropylidene-d-mannitol the allyl carboxylate precursor for the sigmatropic rearrangement was prepared. This rearrangement proc...

Unprecedented stereocontrolled Claisen rearrangement of allylic vinyl ethers has been developed with modified organoaluminum reagents A and B as an example of diastereoselective activation of ethereal substrates. The stereoselective activation of ether moiety is the subject of our current interest. Oxygenophilic organoaluminum reagents are known to exhibit the great tendency to form stable ethe...

Thia-Claisen rearrangements have been carried out using N-benzylpyrrolidine-2-thione and chiral allylic bromides derived from D-mannitol. Introduction of a bromine atom onto the double bond of the allylic bromide reverses the sense of diastereoselectivity in the [3,3]-sigmatropic rearrangement. Density functional theory calculations lead us to rationalise the observed selectivity in terms of a ...

A concise synthesis of homocitric acid lactone was developed to accommodate systematic placement of carbon isotopes (specifically (13)C) for detailed studies of this cofactor. This new route uses a chiral allylic alcohol, available in multigram quantities from enzymatic resolution, as a starting material, which transposes asymmetry through an Ireland-Claisen rearrangement.