37558-43-3Relevant articles and documents
Highly Enantioselective Oxidation of Spirocyclic Hydrocarbons by Bioinspired Manganese Catalysts and Hydrogen Peroxide
Qiu, Bin,Xu, Daqian,Sun, Qiangsheng,Miao, Chengxia,Lee, Yong-Min,Li, Xiao-Xi,Nam, Wonwoo,Sun, Wei
, p. 2479 - 2487 (2018)
Bioinspired manganese complexes have emerged as attractive catalysts for a number of selective oxidation reactions over the past several decades. In the present study, we report the enantioselective oxidation of spirocyclic compounds with manganese complexes bearing tetradentate N4 ligands as catalysts and aqueous H2O2 as a terminal oxidant under mild conditions; spirocyclic tetralone (1a) and its derivatives bearing electron-donating and -withdrawing substituents are converted to their corresponding chiral spirocyclic β,β′-diketones with high yields and enantioselectivities. Spirocyclic indanones are also converted to the β,β′-spirobiindanones with high enantioselectivities. Indeed, the reaction expands the diversity of chiral spirocyclic diketones via a late-stage oxidative process. In addition, it is of importance to note that the catalytic reaction can be easily scaled up and the chiral spirocyclic β,β′-diketones can be transformed into diol products. In mechanistic studies, we have shown that (1) ketones were yielded as products via the initial formation of alcohols, followed by the further oxidation of the alcohols to ketones, (2) hydrogen atom (H atom) abstraction from the methylene C-H bonds of 1a by a putative Mn(V)-oxo intermediate was proposed to be the rate-determining step, and (3) the C-H bond hydroxylation of 1a by the Mn(V)-oxo species was proposed to occur via oxygen rebound mechanism. On the basis of these results, we have proposed a plausible mechanism for the selective C-H bond oxidation of hydrocarbons by bioinspired manganese catalysts and hydrogen peroxide.
Langer,Lehner
, p. 375,376,381 (1973)
Catalytic enantioselective synthesis of chiral spirocyclic 1,3-diketones: Via organo-cation catalysis
Zhang, Xiao-Yan,Shao, Ya-Ping,Guo, Bao-Kuan,Zhang, Kun,Zhang, Fu-Min,Zhang, Xiao-Ming,Tu, Yong-Qiang
supporting information, p. 11233 - 11235 (2021/11/09)
An SPA-triazolium bromide-catalyzed transannular C-acylation of enol lactones is presented. This methodology provides convenient access to a range of enantioenriched spirocyclic 1,3-diketones in moderate to high yields and enantioselectivities and features a broad substrate scope in terms of enol lactones. The catalytic capability of this triazolium salt catalyst is also demonstrated in this enantioselective transformation, which could inspire its further application. This journal is
Catalytic Enantioselective Synthesis of C1- and C2-Symmetric Spirobiindanones through Counterion-Directed Enolate C-Acylation
Rahemtulla, Benjamin F.,Clark, Hugh F.,Smith, Martin D.
supporting information, p. 13180 - 13183 (2016/10/30)
A catalytic enantioselective route to C1- and C2-symmetric 2,2′-spirobiindanones has been realized through an intramolecular enolate C-acylation. This reaction employs a chiral ammonium counterion to direct the acylation of an in situ generated ketone enolate with a pentafluorophenyl ester. This reaction constitutes the first example of a direct catalytic enantioselective C-acylation of a ketone and provides an efficient and highly enantioselective route to axially chiral spirobiindanediones. These products can be diastereoselectively derivatized, offering access to a range of functionalized spirocyclic architectures.
