122822-50-8Relevant articles and documents
Scope and utility of a new soluble copper catalyst [CuBr-LiSPh-LiBr-THF]: A comparison with other copper catalysts in their ability to couple one equivalent of a Grignard reagent with an alkyl sulfonate
Burns, Dennis H.,Miller, Jeffrey D.,Chan, Ho-Kit,Delaney, Michael O.
, p. 2125 - 2133 (1997)
A mixture of equal amounts of CuBr-SMe2, LiBr, and LiSPh in THF at 0°C furnished a new soluble copper catalyst that was highly efficient at coupling primary, secondary, tertiary, aryl, vinyl, and allylic Grignard reagents to primary tosylates and primary Grignard reagents to secondary tosylates and mesylates, all with the use of only 1 equiv of Grignard reagent. The new catalyst was shown to be much more reactive than copper catalysts CuBr and Li2CuCl4 and more efficient in the transference of secondary and tertiary alkyl groups than lower order cuprates (Gilman reagents) and demonstrated more reactivity than the lower order cuprates with its ability to couple primary Grignard reagents to secondary sulfonates. The Grignard reagent/catalyst system was compatible with an ester functionalized tosylate, thus proving to be more chemoselective than a Grignard reagent without the catalyst. The catalyst exhibited good reactivity below room temperature, and with the addition of 6% v/v of HMPA to the catalyst solution, excellent yields of coupled product were obtained within a 25-67°C temperature range. 1H NMR demonstrated that the catalyst solution consisted of several species that most likely were composed of copper ligated with thiophenol, THF, and LiBr in aggregated forms.
Nickel-Catalyzed Decarboxylative Coupling of Redox-Active Esters with Aliphatic Aldehydes
Xiao, Jichao,Li, Zhenning,Montgomery, John
supporting information, p. 21234 - 21240 (2021/12/27)
The addition of alkyl fragments to aliphatic aldehydes is a highly desirable transformation for fragment couplings, yet existing methods come with operational challenges related to the basicity and instability of the nucleophilic reagents commonly employed. We report herein that nickel catalysis using a readily available bioxazoline (BiOx) ligand can catalyze the reductive coupling of redox-active esters with aliphatic aldehydes using zinc metal as the reducing agent to deliver silyl-protected secondary alcohols. This protocol is operationally simple, proceeds under mild conditions, and tolerates a variety of functional groups. Initial mechanistic studies suggest a radical chain pathway. Additionally, alkyl tosylates and epoxides are suitable alkyl precursors to this transformation providing a versatile suite of catalytic reactions for the functionalization of aliphatic aldehydes.
Practical and efficient methods for sulfonylation of alcohols using Ts(Ms)Cl/Et3N and catalytic Me3N · HCl as combined base: Promising alternative to traditional pyridine
Yoshida, Yoshihiro,Sakakura, Yoshiko,Aso, Naoya,Okada, Shin,Tanabe, Yoo
, p. 2183 - 2192 (2007/10/03)
Several alcohols were smoothly and practically tosylated by two methods A and B. Method A uses the TsCl/Et3N (1.5 - 2.5 equiv)/cat. Me3N · HCl (0.1 - 1.0 equiv) reagent. Compared with the traditional Py-solvent method, the method A has merits of its much higher reaction rate, operational simplicity, economy in the use of the amine, and circumvention of the undesirable side reaction from R-OTs to R-CL. Method B uses TsCl/KOH [or Ca(OH)2]/cat. Et3N (0.1 equiv)/cat. Me3N · HCl (0.1 equiv) as the reagent, which will be suited for practical and large scale production for primary alcohols. On both methods A and B, a clear joint action of Et3N and Me3N · HCl catalysts was observed. 1H NMR measurements support the proposed mechanism of the catalytic cycle. Related methanesulfonylation using Et3N and cat. Me3N · HCl in toluene solvent also successfully proceeded, wherein the clear joint action was also observed.
