172925-28-9Relevant articles and documents
Asymmetric total synthesis of cryptoconcatone I
Acharyya, Ranjan Kumar,Pal, Pratik,Chatterjee, Shrestha,Nanda, Samik
, p. 3552 - 3566 (2019)
Asymmetric total synthesis of the naturally occurring cryptoconcatone I, which possesses a γ-Z-butenolide framework, is described here for the first time. Asymmetric propargylation, E-selective cross metathesis, and regioselective reductive epoxide ring o
3,3′-Bithiophene-Based Chiral Bisphosphine Oxides as Organocatalysts in Silicon-Derived Lewis Acid Mediated Reactions
Benaglia, Maurizio,Benincori, Tiziana,Raimondi, Laura Maria,Rossi, Sergio
, p. 535 - 546 (2020/03/27)
This account summarizes the development of new biheteroaromatic chiral bisphosphine oxides. 3,3′-Bithiophene-based phosphine oxides (BITIOPOs) have been successfully used as organocatalysts to promote Lewis base catalyzed, Lewis acid mediated stereoselective transformations. These highly electron-rich compounds, in combination with trichorosilyl derivatives (allyltrichlorosilane and silicon tetrachloride), generate hypervalent silicon species that act as chiral Lewis acids in highly diastereo- and enantioselective organic reactions. Several relevant examples related to these applications are discussed in detail. 1 Introduction 2 The BITIOPO Family 3 Enantioselective Opening of Epoxides 4 Enantioselective Allylation of Aldehydes 5 Stereoselective Direct (Double) Aldol-Type Reaction with Ketones 6 Stereoselective Direct Aldol-Type Reaction with Ester Derivatives 7 Conclusions.
TetraPh-Tol-BITIOPO: A new atropisomeric 3,3′-bithiophene based phosphine oxide as an organocatalyst in Lewis base-catalyzed Lewis acid mediated reactions
Mirco, Abbinante Vincenzo,Maurizio, Benaglia,Sergio, Rossi,Tiziana, Benincori,Roberto, Cirilli,Marco, Pierini
supporting information, p. 7474 - 7481 (2019/08/20)
A new chiral phosphine oxide based on a 3,3′-bithiophene scaffold (TetraPh-Tol-BITIOPO) was synthesized, fully characterized and separated into antipodes through chiral HPLC. This new compound was successfully employed as an organocatalyst in Lewis base-catalyzed Lewis acid mediated reactions involving trichlorosilyl compounds. The new atropisomeric catalyst was able to promote the allylation of aldehydes with allyltrichlorosilane in up to 98% yield and up to 96% enantiomeric excess (ee), and the direct aldol reaction to afford β-hydroxy ketones and β-hydroxy thioesters, with good chemical yields and modest stereochemical efficiency. Computational studies helped to elucidate and to rationalize the stereochemical outcome of the reactions catalyzed by TetraPh-Tol-BITIOPO that was found to favour the formation of the isomer with an opposite absolute configuration in comparison with the products obtained with the previously reported 3,3′-bithiophene-based catalyst.
