Enantioselective, Catalytic One‐Pot Synthesis of
<i>γ</i>
‐Butyrolactone‐Based Fragrances
作者:Ceyda Kumru、Thomas Classen、Jörg Pietruszka
DOI:10.1002/cctc.201801040
日期:2018.11.7
Herein the preparative (1 g scale), stereoselective syntheses of various alkyl‐substituted γ‐butyrolactone fragrances 1 is described. The α,β‐unsaturated γ‐keto esters 2 as starting materials were synthesized by a Horner‐Wadsworth‐Emmons reaction and are further reduced by an ene reductase and alcohol dehydrogenase in a one‐pot enzyme cascade to nine desired γ‐butyrolactones 1, among them whisky (1 c)
Catalytic asymmetric addition of β-keto phosphonates to an activated imine—formation of optically active functionalized phosphonate α-amino acid derivatives
作者:Anne Kjærsgaard、Karl Anker Jørgensen
DOI:10.1039/b416294c
日期:——
stereoselective addition of an activated imine to beta-keto phosphonates in the presence of chiralLewisacidcomplexes is developed. The evaluation of different activated imines shows that an N-tosyl-alpha-imino ester adds in a diastereo- and enantioselective fashion to beta-keto phosphonates activated by especially chiral copper(II)-bisoxazoline complexes. An evaluation of Lewisacids, chiral ligands and
A new methodology has been developed for the P-C bond cleavage of beta-carbonyl phosphonates. The alpha,alpha-disubstituted beta-keto phosphonates and the alpha-carbamoyl phosphonates have been shown to undergo dephosphonylation by reaction of their lithium enolate with LiAlH4, followed by quenching with aqueous H2SO4, affording regioselectively alpha,alpha-disubstituted ketone and alpha-substituted and alpha,alpha-disubstituted secondary amides.
Wittig-Horner Reaction in Heterogeneous Media; V<sup>1</sup>. An Efficient Synthesis of α-Methylenecarboxylic Esters and α-Methyleneketones under Mild Conditions
作者:Jean Villiéras、Monique Rambaud
DOI:10.1055/s-1984-30854
日期:——
Regiocontrolled Synthetic Approach to α,α‘-Disubstituted Unsymmetrical Ketones