23055-11-0Relevant academic research and scientific papers
1,2-carbamoyl migration on enantio-enriched α-lithioalkyl carbamates generated with s-butyllithium/sparteine: Steric course and mechanism
Tomooka, Katsuhiko,Shimizu, Hideo,Inoue, Tadashi,Shibata, Hikaru,Nakai, Takeshi
, p. 759 - 760 (1999)
Alkyl N,N-diisopropylcarbamates, when lithiated with s-BuLi/(-)-sparteine in ether at -78 °C followed by warming to room temperature, are shown to undergo the 1,2-carbamoyl migration to give the α-hydroxy amides in >95% ee with complete retention of configuration at the Li-bearing carbanion terminus. An addition-elimination mechanism is proposed.
A Macrocyclic Ruthenium Carbene for Size-Selective Alkene Metathesis
Diver, Steven T.,Zhang, Yutong
supporting information, (2020/02/22)
The synthesis of a macrocyclic Ru carbene catalyst for selective cross alkene metathesis is reported. The new catalyst showed different reactivity for various type 1 alkenes in homodimerization which correlated with the aggregrate size of the allylic substituent. The altered reactivity profile allowed for selective product formation in competition cross alkene metathesis between two different type 1 alkenes and tert-butyl acrylate. Selectivity in these reactions is attributed to the ability of the macrocyclic catalyst to differentiate alkenes based on their size. Two preparative examples of cross metathesis with the macrocyclic catalyst are also provided.
Unravelling the olefin cross metathesis on solid support. Factors affecting the reaction outcome
Poeylaut-Palena, Andres A.,Mata, Ernesto G.
scheme or table, p. 3947 - 3956 (2010/09/17)
Olefin cross metathesis on solid support under a variety of conditions is described. A comprehensive analysis considering diverse factors governing the reaction outcome gives a series of patterns for the application of this useful methodology in organic synthesis. If the intrasite reaction is not possible, homodimerization of the soluble olefin is crucial. When the homodimer is less reactive than its monomer, reaction outcome depends on the homodimerization rate, which, in turn, depends on the precatalyst used and the reaction conditions. If the site-site interaction is a feasible process, the cross metathesis product is obtained exclusively when the newly-formed double bond is resilient to further metathetic events. Taking into account these considerations, we have demonstrated that excellent results in terms of cross metathesis coupling can be obtained under the optimized conditions, and that microwave irradiation is also an interesting alternative for the development of a practical and energy-efficient cross metathesis on solid support.
Solid-supported cross metathesis and the role of the homodimerization of the non-immobilized olefin
Poeylaut-Palena, Andres A.,Testero, Sebastian A.,Mata, Ernesto G.
, p. 2024 - 2027 (2008/09/19)
(Chemical Equation Presented) We have prepared immobilized olefins as models for the cross metathesis using different olefin partners in the presence of second generation Grubbs and Hoveyda-Grubbs precatalysts. We have demonstrated that solid-phase cross metathesis is strongly dependent on the degree of homodimerization of the non-immobilized olefin and the reactivity of such a homodimer. As in the homogeneous phase, the Hoveyda-Grubbs precatalyst was better for immobilized α,β-unsaturated carbonyl compounds.
Synthesis, reaction, and recycle of light fluorous Grubbs-Hoveyda catalysts for alkene metathesis
Matsugi, Masato,Curran, Dennis P.
, p. 1636 - 1642 (2007/10/03)
(Chemical Equation Presented) Light fluorous versions of first- and second-generation Grubbs-Hoveyda metathesis catalysts are introduced. These exhibit the expected reactivity profile, are readily recovered from reaction mixtures by fluorous solid-phase e
Synthesis of 2,5-dihydrofurans via alkylidene carbene insertion reactions
Walker, Louise F.,Bourghida, Ahmed,Connolly, Stephen,Wills, Martin
, p. 965 - 981 (2007/10/03)
The insertion reaction of alkylidene carbenes is demonstrated to be an effective method for the synthesis of 2,5-dihydrofuran ring systems. The best results have been obtained on substrates containing electron-withdrawing substituents, which appear less prone to the competing rearrangement reaction. This insight has led to the development of a new method for the synthesis of the core structure of the squalestatin-zaragozic acid natural products.
An improved variant of the Julia olefin synthesis: Reductive elimination of β-hydroxy imidazolyl sulfones by samarium diiodide
Kende,Mendoza
, p. 7105 - 7108 (2007/10/02)
The reductive elimination reaction of β-hydroxy imidazolyl sulfones 1 to afford the corresponding olefins can be accomplished under mild conditions and in good yields using SmI2, offering a convenient modification of the Julia olefin synthesis.
A NEW ALKYLTIN(IV)-MEDIATED COUPLING REACTION OF ALDEHYDES TO OLEFINS
Torisawa, Yasuhiro,Shibasaki, Masakatsu,Ikegami, Shiro
, p. 2397 - 2400 (2007/10/02)
Various olefins were synthesized by coupling reactions via the corresponding α-stannylalkyl halides derived from aldehydes.A cross-coupling reaction using the different types of α-stannylalkyl halides, based on the difference of their reactivities, was al
