Asymmetric Catalysis with Ethylene. Synthesis of Functionalized Chiral Enolates
作者:Souvagya Biswas、Jordan P. Page、Kendra R. Dewese、T. V. RajanBabu
DOI:10.1021/jacs.5b10364
日期:2015.11.18
Trialkylsilyl enol ethers are versatile intermediates often used as enolate surrogates for the synthesis of carbonyl compounds. Yet there are no reports of broadly applicable, catalytic methods for the synthesis of chiral silyl enol ethers carrying latent functionalities useful for synthetic operations beyond the many possible reactions of the silyl enol ether moiety itself. Here we report a general
High Reactivity of Strained Seven-Membered-Ring <i>trans</i>
-Alkenes
作者:Jillian R. Sanzone、K. A. Woerpel
DOI:10.1002/anie.201510056
日期:2016.1.11
trans‐Oxasilacycloheptenes are highly reactivestrained alkenes. Competition reactions showed that these seven‐membered ring trans‐alkenes underwent [4+2] cycloaddition reactions faster than a trans‐cyclooctene. They also reacted with quinones and dimethyl acetylenedicarboxylate to form adducts with high diastereoselectivity. Kinetic studies showed that ring strain increases nucleophilicity by approximately
as the solvent and in the presence of a tertiary amine the trimethylchlorosilane/sodium iodide (trimethyliodosilane “in situ”) reagent provides the corresponding siloxy dienes when reacted with α,β-unsaturated series. These reactions occurs via the formation of 1,2 or -1,4 onium salt intermediates.
Asymmetric Diels−Alder Reactions of a New Enantiomerically Pure Sulfinylquinone: A Straightforward Access to Functionalized Wieland−Miescher Ketone Analogues with (<i>R</i>) Absolute Configuration
作者:Don Antoine Lanfranchi、Gilles Hanquet
DOI:10.1021/jo060486n
日期:2006.6.1
highly stereocontrolled preparation, on a large scale, of two new Wieland−Miescher-type diketones is described. The approach centers on a diastereoselective Diels−Alder reaction using a new enantiomericallypure sulfinylquinone. Mechanistic investigations of this cycloaddition on several dienes are described.
The chemistry of aryl-lead(<scp>IV</scp>) tricarboxylates. Reaction with vinylogous β-keto esters
作者:Darren J. Ackland、John T. Pinhey
DOI:10.1039/p19870002689
日期:——
A study of the arylation of ethyl 4-oxocyclohex-2-enecarboxylate and a number of its derivatives by aryl-lead triacetates has been carried out. Ethyl 2-methyl-4-oxocyclohex-2-enecarboxylate (Hagemann's ester)(7), and ethyl 4-oxocyclohex-2-enecarboxylate (10a) and its double bond isomer (10b) were found to undergo regiospecific arylation at C-1 in good yield, whereas the compounds (14) and (16), which