Organocatalytic Dynamic Kinetic Resolution Enabled Asymmetric Synthesis of Phosphorus-Containing Chiral Helicenes.

The catalytic asymmetric synthesis of phosphorus-containing helicenes remains a formidable challenge, presumably due to the lack of rational design of substrates, right choice of reactions together with highly effective catalysis systems. Herein, we disclosed an efficient and practical DKR-involving (dynamic kinetic resolution) cascade strategy toward synthesizing a novel family of phosphorus-installing helicenes by peptide-mimic phosphonium salt (PPS) catalysis. The sequential process of PPS-catalyzed phospha-Michael attack and copper salt-facilitated aromatization led to the formation of unprecedented phosphorus-containing oxa[5]helicene scaffolds. A wide variety of substrates bearing an assortment of functional groups were compatible with this protocol, furnishing the expected helical compounds in high yields and excellent stereoselectivities. Additionally, the helical products could be conveniently elaborated to promising phosphine ligands with perfectly retained helical chirality, which turned out to be highly efficient chiral ligands in transition metal-catalyzed reactions. These findings not only expand the current library of phosphorus-containing helicenes but also offer insights to explore other challenging scaffolds with molecular chirality.

[Application of comfort care for dental out-patients].

OBJECTIVE: To explore and apply the nursing methods of comfort care for dental out-patients. METHODS: Control group included 103 dental out-patients who were first treated in General Dentistry Department of West China Hospital of Stomatology from June to August 2008. Experimental group included 105 dental out-patients who were first treated in the same hospital from September to November 2008. Conventional nursing methods were used for control group, and comfort care nursing methods were used for experimental group. The patients' degree of satisfaction with nursing and oral health knowledge rate after first treatment and nursing were investigated. RESULTS: The patients' degree of satisfaction with nursing of the control and experimental groups were 72.816% and 98.095%, and the patients' oral health knowledge rate of the two groups were 57.282% and 93.333%. Both of the investigating results had obvious difference. CONCLUSION: Comfort care for dental out-patients can improve patients' degree of satisfaction with nursing and increase patients' oral health knowledge rate. Simultaneously, comfort care can improve the specialized quality of dental nurses and would advantage to build a harmonious relationship between nurses and patients.