Copper-Catalyzed Enantioselective 1,2-Allylation of Azadienes with Allylboronates.

Catalytic asymmetric 1,2-allylation of aurone-derived azadienes is very difficult to achieve due to the driving force for aromatization and the greater steric hindrance of 1,2-addition compared with 1,4-addition. By taking advantage of the ability of nitrogen ligated metal complexes, we successfully demonstrated the first example of copper-catalyzed 1,2-allylation of azadienes with allylboronates for the highly enantioselective synthesis of homoallylic amines. Meanwhile, the enantioenriched 1,4-addition products could also be obtained through a subsequent 3,3-sigmatropic rearrangement of the 1,2-addition products. Extensive DFT calculations were carried out to elucidate the origins of high regioselectivity (1,2- vs 1,4-) and enantioselectivity.

Nickel-Catalyzed Three-Component Alkylarylation of Alkenyl N-Heteroarenes.

A nickel-catalyzed three-component alkylarylation of alkenyl N-heteroarenes with α-bromocarboxylates and aryl boronic acids is reported. The protocol provides a new method to access a variety of N-heteroarene substituted diarylalkanes in moderate to good yields. It features mild reaction conditions, cheap nickel catalyst, readily available substrates, and broad substrate scope.

Palladium-Catalyzed Intermolecular Asymmetric Dearomative Annulation of Phenols with Vinyl Cyclopropanes.

Herein, we report the Pd(0)-catalyzed intermolecular asymmetric dearomative [3 + 2] annulation of phenols with vinyl cyclopropanes via in situ generated ortho-quinone methide intermediates. A series of highly functionalized spiro-[5,6] bicycles which bear three contiguous stereogenic centers including one all-carbon quaternary were obtained with excellent stereoselectivities. Density functional theory (DFT) calculations indicate that the reactions were controlled by thermodynamics.

Serum Se, Ni, and As are associated with HPV infection and CIN2+ among Uyghur women in rural China.

BACKGROUND: Cervical cancer incidence and mortality is high in Uyghur ethnics. Their life style and dietary habit were different from other ethnics living together. Study on the role of trace elements in HPV infection and cervical lesion of Uyghur minority is needed for future intervention and prevention work. METHODS: In total, 833 Uyghur women were randomly selected from the screening site and hospital. The concentrations of the trace elements As, Fe, Cd, Ni, Cu, Zn, Mn, and Se were determined by atomic absorption spectrophotometry and inductively coupled plasma atomic emission spectroscopy. Univariate analysis was performed with chi-squared test between the HPV-positive and HPV-negative groups and between the case group and the control group. Multivariate analysis was performed with logistic regression. RESULTS: An As concentration ≥ 0.02 mg/kg was a risk factor for HPV infection (OR > 1, P < 0.05), and Ni concentration ≥ 0.1232 mg/kg and Se concentration ≥ 0.02 mg/kg were protective factors (OR < 1, P < 0.05). Concentrations of Fe ≥ 6.9153 mmol/L and As ≥0.02 mg/kg were risk factors for CIN2+ (OR > 1, P < 0.05), and concentrations of Ni ≥0.0965 mg/kg and Se ≥0.02 mg/kg were protective factors (OR < 1, P < 0.05). CONCLUSIONS: Low serum concentrations of Se and Ni and a high serum concentration of As might be related to HPV infection and CIN2+ in Uyghur women in rural China.