Synthesis of novel P-ketimine bidentate ferrocenyl ligands with central and planar chirality and comparsion in the catalytic activity between P-ketimine and P-aldimine

A series of novel ferrocenylphosphine-ketimine ligands 6 were prepared by reaction of (R,S-p)-PPFNH2-R or (S,S-p)-PPFNH2 with a variety of m-substituted acetophenones. A different catalytic activity was observed between ferrocenylphosphine-ketimine ligands and corresponding aldimine ligands. The efficiency and diastereomeric impact of these ferrocenylphosphine-ketimine ligands in Pd-catalyzed asymmetric allylic alkylation were first investigated, and higher enantioselectivity of over 98% e.e. with 95% yield was obtained by the use of ferrocenylphosphine-ketimine ligands. However, in Rh-catalyzed asymmetric hydrosilylation of aryl ketones, only 42% e.e. was obtained by the use of ferrocenylphosphine-ketimine ligands compared to 90% e.e. with the use of aldimine ligands. (C) 2003 Elsevier Ltd. All rights reserved.

东北产6种苔类植物细胞学观察

本文对东北产 6种苔类植物进行了染色体数目报道 ,它们是阔叶裂叶苔Lophoziaex cisa ,皱叶裂叶苔L .incisa ,倾立裂叶苔L .ascendens,细裂瓣苔Barbilophoziabarbata ,裂萼苔Chiloscyphuspolyanthus,指叶苔Lepidoziareptans,其染色体数目均为n =9。其中阔叶裂叶苔和倾立裂叶苔为首次报道