Chiral Bis(N-sulfonylamino)phosphine- and TADDOL-Phosphite-Oxazoline Ligands: Synthesis and Application in Asymmetric Catalysis
作者:Robert Hilgraf、Andreas Pfaltz
DOI:10.1002/adsc.200404168
日期:2005.1
has been prepared, containing a chiral oxazoline ring and as a second chiral unit a bis(N-sulfonylamino)phosphine group embedded in a diazaphospholidine ring or a cyclic phosphite group derived from TADDOL. These modular ligands are readily synthesized from chiral amino alcohols and chiral 1,2-diamines or TADDOLs. Palladium and iridium complexes derived from these ligands were found to be efficient catalysts
Rhodium(I)-Catalyzed Cycloisomerization
of 1,3-Dienes with Alkenes in a Tether
作者:Yoshihiro Oonishi、Akira Saito、Miwako Mori、Yoshihiro Sato
DOI:10.1055/s-0028-1087973
日期:——
A rhodium(I)-catalyzedcycloisomerization of 1,3-dienes with alkenes in a tether proceeded smoothly, giving cyclopentene or cyclohexene derivatives in good yields. The existence of a hetero atom between the 1,3-diene moiety and the olefin in the tether affected the reaction course. In the case of the substrate having no hetero atom between the 1,3-diene moiety and olefin in the tether, cycloisomerization
Ir-catalysed allylicalkylations of enantiomerically enriched monosubstituted allylic acetates proceed with up to 87% retention of configuration using P(OPh)3 as ligand. High regio- and enantioselectivity of up to 86% ee in asymmetric allylicalkylations of achiral or racemic substrates is achieved with monodentate phosphorus amidites as ligands. Lithium N-tosylbenzylamide was identified as a suitable
使用 P(OPh)3 作为配体,Ir 催化的烯丙基烷基化对映体富集的单取代烯丙基乙酸酯的构型保留率高达 87%。以单齿磷酰胺作为配体,在非手性或外消旋底物的不对称烯丙基烷基化中实现了高达 86% ee 的高区域和对映选择性。N-tosylbenzylamide 锂被确定为适合烯丙基胺化的亲核试剂。特别重要的是使用氯化锂作为添加剂,通常会导致对映选择性增加。通过 X 射线晶体结构分析和光谱数据对两种 (π-烯丙基) IrIII 配合物进行了表征。
Rhodium Complex-Catalyzed Cycloisomerization of Allenenes: Exo and Endo Cyclization Depending on the Auxiliary Ligands
作者:Tatsuya Makino、Kenji Itoh
DOI:10.1021/jo035551x
日期:2004.1.1
having an exo-alkylidene moiety. In this cycloisomerization, (E)- and (Z)-allenenes are transformed stereospecifically to the corresponding cyclic (E)- and (Z)-1,4-dienes, respectively. On the other hand, the reactions under carbon monoxide atmosphere exclusively afford seven-membered-ring products through an endo-mode cyclization. The unusual cyclization involves an allylic C−H activation process. The
The branched, chiral products 1 are formed preferentially in the allylicalkylations in Equation (1) when the Pd catalyst contains the P,N ligand L* or derivatives thereof. The ligands are readily synthesized from commercially available precursors.