A FACILE ASYMMETRIC SYNTHESIS OF β-SUBSTITUTED ALKANOIC ACID THE HIGHLY STEREOSELECTIVE MICHAEL ADDITION OF GRIGNARD REAGENTS TO α,β-UNSATURATED CARBOXYLIC AMIDES DERIVED FROM L-EPHEDRINE
作者:Teruaki Mukaiyama、Nobuharu Iwasawa
DOI:10.1246/cl.1981.913
日期:1981.7.5
The Michael addition of Grignard reagents to chiral α,β-unsaturated carboxylic amides derivedfrom 1-ephedrine affords highly optically active β-substituted alkanoic acids after acid hydrolysis. This high stereoselectivity is explained by considering the formation of rigid internal chelate complexes.
Asymmetric conjugate addition reaction by the use of ()-γ-trityloxymethyl-γ-butyrolactam as a chiral auxiliary
作者:Kiyoshi Tomioka、Toshiro Suenaga、Kenji Koga
DOI:10.1016/s0040-4039(00)84021-6
日期:1986.1
(S)-γ-Trityloxymethyl-γ-butyrolactam (2) serves as a chiralauxiliary in the conjugate addition reaction of the corresponding imide (3) of α,β-unsaturated carboxylic acids with Grignard reagents in the presence of CuBrSMe2 in THF to give, after hydrolysis, the β,β-disubstituted carboxylic acids (5) with predictable absolute configuration and high enantiomeric excess.
Enantioselective Carbometalation of Cinnamyl Derivatives: New Access to Chiral Disubstituted Cyclopropanes— Configurational Stability of Benzylic Organozinc Halides
作者:Stephanie Norsikian、Ilan Marek、Sophie Klein、Jean F. Poisson、Jean F. Normant
Enantioselective Carbolithiation of β-Alkylated Styrene
作者:Stephanie Norsikian、Ilane Marek、Jean-F Normant
DOI:10.1016/s0040-4039(97)10022-3
日期:1997.10
Stoichiometric or catalytic amounts of (-) sparteine serve as promoter for enantioselective carbolithiation of beta-alkylated, non functionalized styrene. (C) 1997 Published by Elsevier Science Ltd.
Copper‐Catalyzed Enantioselective Conjugate Addition of Dialkylzinc Reagents to α′‐Oxy Enones
作者:Jesús M. García、Alberto González、Bharat G. Kardak、José M. Odriozola、Mikel Oiarbide、Jesús Razkin、Claudio Palomo