Stereoselective Synthesis of Bicyclic Tertiary Alcohols with Quaternary Stereocenters via Intramolecular Crossed Benzoin Reactions Catalyzed by <i>N</i>-Heterocyclic Carbenes
Bicyclic tertiary alcohols 1 bearing quaternary stereocenters at the two adjacent bridgehead positions were synthesized with high stereoselectivity via the intramolecular crossed benzoin reactions catalyzed by NHC organocatalysts.
Efficient Construction of Polycyclic Derivatives via a Highly Selective Cu<sup>I</sup>-Catalyzed Domino Reductive-Aldol Cyclization
作者:Julia Deschamp、Olivier Riant
DOI:10.1021/ol802879f
日期:2009.3.19
A versatile methodology for the diastereo- and enantioselective domino reductive-aldol cyclizations is reported. By using a copper (I)/diphosphane ligand, various five- and six-membered rings were generated with good to excellent diastereo- and enantioselectivities (cis:trans up to 100:0 and ee up to 95%).
An easy route toward enantio-enriched polycyclic derivatives via an asymmetric domino conjugate reduction–aldol cyclization catalyzed by a chiral Cu(I) complex
作者:Julia Deschamp、Thomas Hermant、Olivier Riant
DOI:10.1016/j.tet.2011.07.039
日期:2012.4
A highlyefficient reductive-aldol cyclization mediated by a chiral Cu(I) complex and an organosilane yielded to cyclic or polycyclic derivatives. An excellent control of the selectivities was reached in most cases (dr up to 100:0 and ee up to 95%). After developing the enantioselective intramolecular reductive-aldol methodology, this strategy was successfully used for the synthesis of a key intermediate
Construction of Contiguous Tetrasubstituted Carbon Stereocenters by Intramolecular Crossed Benzoin Reactions Catalyzed by N-Heterocyclic Carbene (NHC) Organocatalyst
Bicyclic compounds with two contiguous tetrasubstituted carbon stereocenters at bridgehead positions were synthesized by N-heterocyclic carbene (NHC)-catalyzed intramolecular crossed benzoin reactions of symmetrical compounds. This desymmetrization strategy was applied to asymmetricsynthesis with chiral NHC organocatalysts. Transition-state models were proposed to explain the enantioselectivity. A