Highly Stereoselective Anti SN2‘ Substitutions of (Z)-Allylic Pentafluorobenzoates with Polyfunctionalized Zinc−Copper Reagents
摘要:
[GRAPHICS]Allylic substitution reactions of zinc-copper organometallics on (Z)-allylic pentafluorobenzoates proceed with very high regioselectivity and excellent anti selectivity. The high fidelity in transfer of stereochemical information allowed a short synthesis of (+)-ibuprofen (97% ee).
Highly Stereoselective Anti SN2‘ Substitutions of (Z)-Allylic Pentafluorobenzoates with Polyfunctionalized Zinc−Copper Reagents
摘要:
[GRAPHICS]Allylic substitution reactions of zinc-copper organometallics on (Z)-allylic pentafluorobenzoates proceed with very high regioselectivity and excellent anti selectivity. The high fidelity in transfer of stereochemical information allowed a short synthesis of (+)-ibuprofen (97% ee).
Chiral-Anion-Mediated Asymmetric Heck–Matsuda Reaction of Acyclic Alkenyl Alcohols
作者:Tao Zhang、Wen-Ao Li、Hong-Cheng Shen、Shu-Sen Chen、Zhi-Yong Han
DOI:10.1021/acs.orglett.1c00152
日期:2021.2.19
Acyclic internal alkenes are a class of challenging substrates in asymmetric Heck-type reactions due to difficulties related to both reactivity and selectivity control. Employing acyclic alkenyl alcohols, an asymmetric Heck–Matsuda reaction is developed through the strategy of chiral anion phase transfer. Various chiral ketones could be obtained in high levels of enantioselectivity. A catalytic amount
Copper-Catalyzed γ-Selective and Stereospecific Allylic Alkylation of Ketene Silyl Acetals
作者:Dong Li、Hirohisa Ohmiya、Masaya Sawamura
DOI:10.1021/ja111645q
日期:2011.4.20
Copper-catalyzed allylic alkylation of ketene silyl acetals proceeded with excellent γ-E-selectivity. Efficient α-to-γ chirality transfer with anti-selectivity occurred in the reaction of enantioenriched secondary allylic phosphates, affording enantioenriched β-branched γ,δ-unsaturated esters. Excellent functional group compatibility was observed.
The first asymmetric Cu-catalyzed conjugate addition of dialkylzinc zinc reagents to a large scope of enals in presence of phosphoramidite, SimplePhos, or (R)-BINAP ligands with enantiomeric excesses up to 90% is reported. Moreover, ACA of Grignard reagents afforded moderate to good 1,4-regioselectivities with enantioselectivities up to 90%.
Reactivity and regio- and enantioselectivities were strongly dependent on reaction conditions and substrates. Good to excellent regio- and enantioselectivities were obtained with zinc reagents R2Zn and aluminum reagents R3Al. However, the asymmetric conjugate addition of Grignard reagents afforded only moderate to good regio- and enantioselectivities. β-Substituted aldehydes constitute a very important
PRECURSOR COMPOUNDS OF SWEET TASTE RECEPTOR ANTAGONISTS FOR THE PREVENTION OR TREATMENT OF DISEASE
申请人:Ley Jakob Peter
公开号:US20110045069A1
公开(公告)日:2011-02-24
A description is given of precursor compounds of sweet taste receptor antagonists for the prevention or treatment of disease, in particular for the prevention or treatment of Type 2 diabetes.
A description is also given of uses of these precursor compounds and edible compositions, preparations for nutrition or pleasure or semi-finished products and pharmaceutical preparations, containing such precursor compounds.