The synthesis of non-racemic β-alkyl-β-aryl-disubstituted allyl alcohols and their transformation into allylamines and amino acids bearing a quaternary stereocenter
synthesis of non-racemic β-alkyl-β-aryl allyl alcohols and their transformation into allylamines bearing a quaternary stereogenic center is reported. The allyl alcohols were prepared either by Cu-catalyzed enantioselective reduction of enones or by sequential alkylation/hydrostannylation/Stille coupling of non-racemic propargyl alcohols. The prepared β-alkyl-β-aryl allyl alcohols were converted (after carbamoylation)
Synthesis of optically active alkynyl alcohols and α-hydroxy esters by microbial asymmetric hydrolysis of the corresponding acetates
作者:Kenji Mori、Hiroko Akao
DOI:10.1016/0040-4020(80)85030-7
日期:1980.1
Asymmetric hydrolysis of the acetates of racemic alkynyl alcohols and α-hydroxy esters by Bacillus subtilis var. Niger afforded optically active acetates and alcohols in 7–90% optical purities. The both enantiomers of optically pure mandelie acid were prepared by this microbial method.
Mechanistic aspects of the formation of chiral allenes from propargylic ethers and organocopper reagents
作者:A. Alexakis、I. Marek、P. Mangeney、J. F. Normant
DOI:10.1021/ja00178a029
日期:1990.10
Propargylic ethers react with organocopperreagents to afford allenes by a syn addition to the triple bond followed by a β-elimination of the resulting alkenyl copper species. With use of chiral propargylic ethers and stoichiometric organocopperreagent, it was shown that the β-elimination step is purely anti, resulting in the formation of a chiral allene with 96% optical yield. The same reaction,
炔丙醚与有机铜试剂反应,通过对三键进行顺式加成,然后β-消除生成的烯基铜物质来提供丙二烯。使用手性炔丙醚和化学计量有机铜试剂,表明 β-消除步骤是纯反的,导致形成具有 96% 光学产率的手性丙二烯。使用格氏试剂 RMgX 和催化量的 Cu I 盐进行相同的反应,通过反或顺整个过程提供丙二烯。关键的步骤是β-消除中间体烯基有机金属物种,它是反型与 RMgI 和顺型与 RMgCl。丙炔乙酸酯,在该反应中也提供丙二烯,但通过 Cu III 中间体,对这种“卤素效应”不敏感
Diastereo- and Enantioselective Propargylation of Benzofuranones Catalyzed by Pybox-Copper Complex
Diastereo- and enantioselective preparation of 2,2-disubstituted benzofuran-3(2H)-one has been realized by a pybox-copper catalyzed reaction between 2-substituted benzofuran-3(2H)-one and propargyl acetate. The utility of this method was demonstrated by further transformation of the terminal alkyne into a methyl ketone without loss of enantiomeric purity.
Synthesis of optically active alkynyl alcohols by microbial asymmetric hydrolysis of the corresponding acetates