Enantioselective organocatalytic formal allylation of α-branched aldehydes
作者:Eduardo Rodrigo、Sara Morales、Sara Duce、José Luis García Ruano、M. Belén Cid
DOI:10.1039/c1cc14909a
日期:——
Heteroarylvinyl sulfone 1 has been successfully used as a new sulfonyl Michael acceptor in aminocatalytic reactions with branched aldehydes. Subsequent one-pot JuliaâKocienski olefination allows the challenging preparation of enantiomerically pure α-allylated aldehydes bearing C-α quaternary carbons.
Chiral Counteranions in Asymmetric Transition-Metal Catalysis: Highly Enantioselective Pd/Brønsted Acid-Catalyzed Direct α-Allylation of Aldehydes
作者:Santanu Mukherjee、Benjamin List
DOI:10.1021/ja074678r
日期:2007.9.1
Pd/chiral acid-catalyzed α-allylation of α-branched aldehydes with an allyl amine as the allylating species that creates all-carbonquaternary stereogenic centers in high yields and enantioselectivities. To our knowledge, this is the first time that a chiral anionic ligand is applied for achieving asymmetric induction in a palladium-catalyzedallylicalkylation reaction.
Asymmetric induction reactions. IV. Palladium-catalyzed asymmetric allylations of chiral enamines bearing phosphine groups.
作者:Kunio HIROI、Jun ABE
DOI:10.1248/cpb.39.616
日期:——
The palladium-catalyzed asymmetric allylations of chiral enamines, derived from (S)-2-(diphenylphosphinomethyl)pyrrolidine, produced optically active α-allyl carbonyl compounds in high optical yields. The phosphino group in the chiral enamines presumably serves as a chiral ligand in these palladium-catalyzed reactions. In the transition states of π-allylpalladium complexes coordinated with the intramolecular phosphine group, the anionic counterparts or allylating reagents are considered to play an important role in controlling of the grade of the enantioselectivity.
nickel and chiralamine cooperative catalysis to enable a highlyenantioselectiveallylic alkylation reaction between α-branched aldehydes and a wide scope of allyl esters, allowing the all-carbon quaternary stereocenter to be accessed with excellent enantioselectivity (up to 98% ee) and structural diversity. The general synthetic applicability has been showcased by the enantioselective synthesis of
全碳四元立体中心构成了天然产物和生物活性化合物的重要组成部分。在这里,我们公开了一种镍和手性胺协同催化,使 α-支化醛和各种烯丙基酯之间发生高度对映选择性的烯丙基烷基化反应,从而以优异的对映选择性(高达 98% ee ) 和结构多样性。关键手性构件的对映选择性合成以获取 (+)-依他佐辛、(-)-aphanorphine 和其他两种生物活性化合物,展示了一般合成适用性。
Organocatalytic Asymmetric α-Allylation and Propargylation of α-Branched Aldehydes with Alkyl Halides
作者:Masanori Yoshida
DOI:10.1021/acs.joc.1c01394
日期:2021.8.6
Enantioselective α-allylation and -propargylation of α-branched aldehydes with alkyl halides was successfully performed using a chiral primary amino acid organocatalyst. This alkylation reaction, involving the generation of a chiral quaternary carbon stereocenter, proceeded smoothly in a mildly basic aqueous solution of potassium hydrogen carbonate to furnish α-allylated or -propargylated aldehydes