27345-72-8Relevant articles and documents
Applying the Bent Bond/Antiperiplanar Hypothesis to the Stereoselective Glycosylation of Bicyclic Furanosides
Parent, Jean-Fran?ois,Bertrand, Xavier,Deslongchamps, Ghislain,Deslongchamps, Pierre
, p. 758 - 773 (2020/01/11)
The glycosylation stereoselectivities for a series of bicyclic furanoside models have been carried out in the presence of weak nucleophiles. These results were analyzed through the bent bond/antiperiplanar hypothesis (BBAH) orbital model to test its validity. According to the BBAH, incoming nucleophiles displace one of the two bent bonds of bicyclic oxocarbenium ion intermediates in an antiperiplanar fashion. The glycosylation stereoselectivity is then governed by the displacement of the weaker bent bond as determined by the presence of electron-withdrawing or -donating substituents at C2. Overall, the BBAH analysis expands Woerpel's "inside/outside attack" glycosylation model by considering the stereoelectronic influence of neighboring electron-withdrawing and -donating groups on the nucleophilic addition to oxocarbenium ion intermediates.
Carboxylates as Nucleophiles in the Enantioselective Ring-Opening of Formylcyclopropanes under Iminium Ion Catalysis
Díaz, Estibaliz,Reyes, Efraim,Uria, Uxue,Carrillo, Luisa,Tejero, Tomas,Merino, Pedro,Vicario, Jose L.
supporting information, p. 8764 - 8768 (2018/05/30)
In this work, carboxylic acids, which are typically regarded as poor nucleophiles, are demonstrated to be competent reagents to promote the ring-opening of formylcyclopropanes after activation of the latter through iminium ion formation. Under optimized r
Asymmetric reduction of substituted indanones and tetralones catalyzed by chiral dendrimer and its application to the synthesis of (+)-sertraline
Wang, Guangyin,Zheng, Changwu,Zhao, Gang
, p. 2074 - 2081 (2007/10/03)
A recoverable dendrimeric supported prolinol was used as a catalyst in the asymmetric reduction of indanones and tetralones to give separable cis and trans isomers up to 97% ee. This method was also applied in the enantioselective synthesis of the antidepressant drug (+)-sertraline.
Unique Synthetic Utility of BF3*OEt2 in the Highly Diastereoselective Reduction of Hydroxy Carbonyl and Dicarbonyl Substrates
Ooi, Takashi,Uraguchi, Daisuke,Morikawa, Junko,Maruoka, Keiji
, p. 2015 - 2018 (2007/10/03)
. A new aspect of commonly used BF3*OEt2 has been illuminated by successfully demonstrating the unique but highly stereoselective reactions of hydroxy carbonyl and dicarbonyl substrates. For example, treatment of γ-hydroxy ketone 1c with BF2*OEt2/Bu3SnH in CH2Cl2 at -78 to -40 deg C afforded the corresponding 1,4-diol 2c with virtually complete diastereoselection, while use of TiCl4 as a Lewis acid under similar reaction conditions caused a total lack of diol yield and selectivity (17%; 2c/3c = 1.2:1), accompanied by a significant formation of 2,3-disubstituted tetrahydrofuran 4 (44%).
PREPARATION OF 7-OXABICYCLONONANES AND 2-OXABICYCLODECANES SPECIFICALLY LABELLED WITH DEUTERIUM
Turecek, Frantisek
, p. 858 - 876 (2007/10/02)
trans-Annulated 7-oxabicyclononanes, labelled with deuterium at C(1), C(6), C(8) and C(9), and cis-annulated isomers labelled at C(1) and C(6) were prepared by cyclization of the cor
