7731-16-0Relevant academic research and scientific papers
Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols
Ye, Ke-Yin,Mccallum, Terry,Lin, Song
supporting information, (2019/06/24)
Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely, bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton transfer/electron transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.
The Diels-Alder Route to Allylsilanes from 1-Trimethylsilylbutadienes
Carter, Martin J.,Fleming, Ian,Percival, Alan
, p. 2415 - 2434 (2007/10/02)
The synthesis and Diels-Alder reactions of 1-trimethylsilylbutadiene (3) and its 3-methyl (17), 3-trimethylsilyloxy (20), 4-methyl (4), and 4-trimethylsilyl (6) derivatives are reported.The silyl group reduces somewhat the rate of the Diels-Alder reactions, and has, if anything, a small 'ortho'-directing effect on the regioselectivity in the reactions of (3) with methyl acylate, methyl propiolate, citraconic anhydride, and 2,6-dimethylbenzoquinone.The other substituent in the dienes (17), (20), and (4) is therefore the major influence on the regioselectivity in the reactions of these dienes with methyl acrylate and methyl propiolate.The products of the Diels-Alder reactions of (3), (17), and (4) are allylsilanes, which undergo clean protodesilylation with acid, and, with the acid and ester derived from the maleic anhydride adduct of (3), undergo epoxidation and sulphenylation reactions giving an allyl alcohol (33) and an allyl sulphide (37), respectively.The adducts from (20) can be hydrolysed to β-silylketones, which can be converted into enones by bromination. 1-Pentamethyldisilylbutadiene (15) is no more reactive and no more regioselective than (3).The 'ortho'-adduct (42) from the reaction of (3) and methyl propiolate aromatises with DDQ to give methyl m-trimethylsilylbenzoate (53) in high yield, in a reaction involving rearrangement of the silyl group, even though a direct dehydrogenation is an available pathway.
