The iridium-catalyzed highly enantioselective hydrogenation of alpha-aryloxy and alpha-alkoxy-substituted alpha,beta-unsaturated carboxylic acids was developed. By using chiral spiro phosphino-oxazoline ligands, the hydrogenation proceeded smoothly to produce various alpha-aryloxy- and alpha-alkoxy-substituted carboxylic acids with extremely high enantioselectivities (ee up to 99.8%) and reactivities (TON up to 10,000) under mild conditions.
View Article and Find Full Text PDFA highly efficient iridium-catalyzed hydrogenation of alpha,beta-unsaturated carboxylic acids has been developed by using chiral spiro-phosphino-oxazoline ligands, affording alpha-substituted chiral carboxylic acids in exceptionally high enantioselectivities and reactivities.
View Article and Find Full Text PDFZhonghua Liu Xing Bing Xue Za Zhi
September 2005
Objective: To understand the timeliness of the notifiable communicable diseases surveillance system in Fujian province.
Methods: Database from the internet based communicable diseases reporting system was used.
Results: The 50th percentile of time between the disease diagnosed and report recorded in medical faculties was 1 day in 2004 which was 6 days less than that in 2001 - 2003.
Zhonghua Liu Xing Bing Xue Za Zhi
October 2004