A highly enantioselectivecyanosilylation of ketones was developed by using a chiral lithium(I) phosphoryl phenoxide aqua complex as an acid/base cooperative catalyst. The pentacoordinate silicate generated in situ from Me3SiCN/LiCN acts as an extremely reactive cyano reagent. Described is a 30 gram scale reaction and the synthesis of the key precursor to (+)‐13‐hydroxyisocyclocelabenzine.
Synthesis of hybrid dendritic molecules with diazaphospholidine oxide grafted at the surface of octavinylsilsesquioxane (OVS)
作者:Ge Cheng、Alexandra M. Z. Slawin、Nicolas R. Vautravers、Pascal André、Russell E. Morris、Ifor D. W. Samuel、David Cole-Hamilton
DOI:10.1039/c0ob00297f
日期:——
phosphine oxide ligand, which was derivatised with a series of functional groups including bromide, vinyl, allyl and terminal alkyne. Several methods to attach the resulting precursors onto octavinylsilsesquioxane (OVS), ranging from hydrosilylation, Suzuki, Heck, Grubbs or Sonogashira coupling reactions, have been investigated. Cross-metathesis of SEMI-ESPHOS oxide dendrons containing vinyl end groups
Synthesis and applications to asymmetric catalysis of a series of mono- and bis(diazaphospholidine) ligands
作者:Donald Smyth、Heather Tye、Colin Eldred、Nathaniel W. Alcock、Martin Wills
DOI:10.1039/b106399p
日期:2001.11.1
The synthesis of a series of closely related mono- and bis(diazaphospholidine) ligands has been achieved using the condensation of a diamine with a bis(dimethylamino)arylphosphine. The resulting ligands have given excellent results in palladium-catalysed allylic substitution reactions to form C–C bonds (up to 89% ee) and C–N bonds (up to 78% ee).
Synthesis and application to asymmetric allylic amination of substituted monodonor diazaphospholidine ligands
作者:Christopher W Edwards、Mark R Shipton、Nathaniel W Alcock、Howard Clase、Martin Wills
DOI:10.1016/s0040-4020(03)01062-7
日期:2003.8
The synthesis of a series of substituted monodonor diazaphospholidine ligands is described. A regioselective lithiation process is a key step in one of these syntheses. The compounds are designed to be incorporated into soluble polymer and other solid phase supports. Enantiomeric excesses of up to 88% were observed when these compounds were employed in palladium-catalysed asymmetric amination reactions
The synthesis and applications to allylic substitutions of a range of
novel ligands based on diazaphospholidines is described; enantiomeric
excesses of up to 89% were achieved in an allylic substitution
reaction.