39815-00-4Relevant academic research and scientific papers
t-BuOK promoted stereoselective isomerization of allyl aryl ethers
Shi, Mingqi,Wang, Liang,Chen, Qun,He, Mingyang,Shen, Minggui,Zhang, Zhi-hui
supporting information, (2020/08/06)
The t-BuOK promoted stereoselective isomerization of allyl aryl ethers has been developed. The reactions proceeded well in methyl tert-butyl ether (MTBE), providing the corresponding products in good to excellent yields (83–96percent). Most of the substra
Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 15. Generation of alkoxycarbonyl(sulfenyl)carbenes and their intramolecular insertion to give alkenyl sulfides
Aitken, R. Alan,Armstrong, Jill M.,Drysdale, Martin J.,Ross, Fiona C.,Ryan, Bruce M.
, p. 593 - 604 (2007/10/03)
A range of 18 alkoxycarbonyl sulfinyl phosphorus ylides 9 have been prepared and their behaviour upon flash vacuum pyrolysis (FVP) at 600 deg C examined. For R1 = H, Me and Et they lose Ph3PO and in some cases Ph3P to give mixtures of products including the alkenyl sulfides 10, the sulfides 11, the disulfides 12 and the thioesters 14. The alkenyl sulfides 10 most likely arise from intramolecular insertion of the alkoxycarbonyl sulfenyl carbenes resulting from loss off Ph3PO to produce β-lactones which then lose CO2 and this is supported by the results from 13C labelled ylides. Possible mechanisms for the formation of 11 and 14 are also presented and the feasibility of various steps has been examined by preparation and pyrolysis of the proposed intermediates. In contrast, pyrolysis of the ylides 9 where R1 = Ph and the tert-butoxycarbonyl ylides 30 leads mainly to complete fragmentation with loss of Ph3PO and benzyl alcohol or 2-methylpropan-2-ol and does not give any useful sulfur-containing products. Four alkoxy-carbonyl sulfonyl diazo compounds 33 have been prepared and in three cases they give the alkenyl sulfones 34 upon FVP at 400 deg C, probably by an intramolecular insertion and decarboxylation process analogous to the formation of 10 from 9. On the other hand the alkoxycarbonyl carbenes produced by FVP of the amino acid-derived diazo compounds 35 undergo alternative proocesses with no sign of β-lactone formation. Fully assigned 13C NMR data are presented for 13 of the ylides.
Insertion of Carbon Monoxide into Allylic Carbon-Sulfur Bonds Catalyzed by Palladium and Ruthenium Complexes
Crudden, Cathleen M.,Alper, Howard
, p. 5579 - 5587 (2007/10/03)
The metal complex-catalyzed insertion of carbon monoxide into the C-S bond of various allylic sulfides affords thioesters in up to 88percent yield.The reaction is catalyzed by various palladium complexes, with concomitant isomerization of the olefin into conjugation with the carbonyl group.In these cases, only the trans isomer was detected by 1H NMR spectroscopy.Ruthenium complexes also catalyzed the carbonylation but the initially formed β,γ-thioester was not isomerized.
Flash Vacuum Pyrolysis of Alkoxycarbonyl/Sulfinyl Stabilised Phosphorus Ylides: Generation and Intramolecular Insertion of Alkoxycarbonyl(sulfenyl)carbenes
Aitken, R. Alan,Drysdale, Martin J.,Ryan, Bruce M.
, p. 805 - 806 (2007/10/02)
Flash vacuum pyrolysis of phosphorus ylides stabilised both by ester and sulfinyl groups results mainly in extrusion of Ph3PO to generate alkoxycarbonyl(sulfenyl)carbenes; these undergo intramolecular insertion into CH of the alkoxycarbonyl group giving β-lactones which under the conditions lose CO2 to afford alkenyl sulfides.
