821-74-9Relevant academic research and scientific papers
Intermolecular Allene Functionalization by Silver-Nitrene Catalysis
Rodríguez, Manuel R.,Besora, María,Molina, Francisco,Maseras, Feliu,Díaz-Requejo, M. Mar,Pérez, Pedro J.
, p. 13062 - 13071 (2020/09/01)
Under silver catalysis conditions, using [Tp*,BrAg]2 as the catalyst precursor, allenes react with PhI═NTs in the first example of efficient metal-mediated intermolecular nitrene transfer to such substrates. The nature of the substituent at the allene seems crucial for the reaction outcome since arylallenes are converted into azetidine derivatives, whereas methylene aziridines are the products resulting from alkylallenes. Mechanistic studies allow proposing that azetidines are formed through unstable cyclopropylimine intermediates, which further incorporate a second nitrene group, both processes being silver-mediated. Methylene aziridines from alkylallenes derive from catalytic nitrene addition to the allene double bonds. Both routes have resulted to be productive for further synthetic transformations affording aminocyclopropanes.
Ketonitrones via cope-type hydroamination of allenes
Moran, Joseph,Pfeiffer, Jennifer Y.,Gorelsky, Serge I.,Beauchemin, Andre M.
supporting information; experimental part, p. 1895 - 1898 (2009/09/08)
The synthesis of ketonitrones from W-alkylhydroxylamines and monosubstituted allenes is accomplished via a Cope-type hydroamination reaction in moderate to good yields. Allenes also undergo a similar reaction with aqueous hydroxylamine to give oximes in e
Rearrangements and stereomutations of metallacycles derived from allenes and imidozirconium complexes
Michael, Forrest E.,Duncan, Andrew P.,Sweeney, Zachary K.,Bergman, Robert G.
, p. 1752 - 1764 (2007/10/03)
The mechanisms of the rearrangements and Stereoinversion of azametallacyclobutenes generated via [2+2] cycloaddition of allenes and imidozirconium complexes have been studied. Metallacycles derived from allenes bearing β-hydrogen atoms racemize at room temperature by reversible β-hydride elimination, a process which is also responsible for their eventual conversion to monoazadiene complexes. Metallacycles derived from diarylallenes racemize by reversible thermal bond homolysis at 95°C; racemization of these metallacycles is also catalyzed by mild oxidants.
Enantioselective and regioselective nickel-catalyzed multicomponent coupling of chiral allenes, aromatic aldehydes, and silanes
Ng, Sze-Sze,Jamison, Timothy F.
, p. 11405 - 11417 (2007/10/03)
A detailed account of the development of a recently developed, nickel-catalyzed multicomponent coupling of chiral allenes, aromatic aldehydes, and silanes is described. The axial chirality of the allene is transferred completely to the product, a trisubstituted Z-allylic alcohol protected as a silyl ether. A very high preference for sp rather than sp2 coupling is observed, and differentially substituted allenes undergo highly site-selective coupling. These transformations represent the first enantioselective multi-component coupling processes of allenes.
1,4-Dioxaspiropentanes. Synthesis, Spectroscopic Properties, and Reactions with Nucleophiles
Crandall, Jack K.,Batal, David J.,Sebesta, David P.,Lin, Feng
, p. 1153 - 1166 (2007/10/02)
A number of simple allenes have been converted cleanly to the corresponding 1,4-dioxaspiropentanes in good yields by oxidation with dimethyldioxirane.Mono- and trisubstituted allenes give the anti diastereomers with good stereoselectivity, whereas 1,3-disubstituted allenes show only a slight preference for the anti,anti isomers, unless steric effects are extreme.Stereochemical assignments are based on steric considerations and a consistent set of NMR characteristics that permit structural attributions.The addition of a range of nucleophiles (water, alcohols, amines, thiophenol, acetate, chloride, and fluoride) to these intermediates proceeded smoothly under buffered conditions to give highly functionalized products of general type 5.These reactions were shown to take place with the appropriate selectivities for SN2 substitutions in instances where these features were observable, namely, regioselective attack at the less-substituted epoxide carbon and inversion of configuration at the site of substitution.Under acid conditions dioxaspiropentanes gave mixtures of other types of products, which appear to arise from carbocationic processes.
