The use of alcohols and unsaturated reactants for the redox‐triggered generation of nucleophile–electrophile pairs represents a broad, new approach to carbonyl addition chemistry. Discrete redox ...manipulations that are often required for the generation of carbonyl electrophiles and premetalated carbon‐centered nucleophiles are thus avoided. Based on this concept, a broad, new family of enantioselective CC coupling reactions that are catalyzed by iridium or ruthenium complexes have been developed, which are summarized in this Minireview.
Borrowing with interest: The concept of exploiting alcohols and unsaturated reactants for the redox‐triggered generation of nucleophile–electrophile pairs reinvents the chemistry of carbonyl addition, enabling a broad, new family of catalytic enantioselective CC couplings.
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Olefin metathesis is an incredibly valuable transformation that has gained widespread use in both academic and industrial settings. Lately, stereoretentive olefin metathesis has garnered much ...attention as a method for the selective generation of both E‐ and Z‐olefins. Early studies employing ill‐defined catalysts showed evidence for retention of the stereochemistry of the starting olefins at low conversion. However, thermodynamic ratios E/Z were reached as the reaction proceeded to equilibrium. Recent studies in olefin metathesis have focused on the synthesis of catalysts that can overcome the inherent thermodynamic preference of an olefin, providing synthetically useful quantities of a kinetically favored olefin isomer. These reports have led to the development of stereoretentive catalysts that not only generate Z‐olefins selectively, but also kinetically produce E‐olefins, a previously unmet challenge in olefin metathesis. Advancements in stereoretentive olefin metathesis using tungsten, ruthenium, and molybdenum catalysts are presented.
Make your choice: The idea of stereoretentive olefin metathesis to kinetically generate both E‐ or Z‐olefins has shown great promise of late and has encouraged the synthesis of new metathesis catalysts. Recent advancements using tungsten, ruthenium, and molybdenum catalysts are presented in this Minireview.
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Olefin metathesis is a prevailing method for the construction of organic molecules. Recent advancements in olefin metathesis have focused on stereoselective transformations. Ruthenium olefin ...metathesis catalysts have had a particularly pronounced impact in the area of stereoselective olefin metathesis. The development of three categories of Z-selective olefin metathesis catalysts has made Z-olefins easily accessible to both laboratory and industrial chemists. Further design enhancements to asymmetric olefin metathesis catalysts have streamlined the construction of complex molecules. The understanding gained in these areas has extended to the employment of ruthenium catalysts to stereoretentive olefin metathesis, the first example of a kinetically E-selective process. These advancements, as well as synthetic applications of the newly developed catalysts, are discussed.
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Trifluoromethyl substituted allenes engage in ruthenium catalyzed reductive couplings with paraformaldehyde to form products of hydrohydroxymethylation as single regioisomers. This method enables ...generation of CF3-bearing all-carbon quaternary stereocenters.
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A new benzannulation protocol is described and applied to the synthesis of polycyclic aromatic hydrocarbons. Ruthenium(0)-catalyzed diol–diene 4+2 cycloaddition delivers cyclohex-1-ene-4,5-diols, ...which are subject to aromatization upon dehydration or Nicholas diol deoxydehydration. Employing diol and tetraol reactants, benzannulation can be conducted efficiently in one- and two-directional modes, respectively, as illustrated in the construction of substituted fluoranthenes and acenes.
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Indazoles represent a privileged motif in drug discovery. However, the formation of highly substituted indazoles can require the execution of lengthy synthetic routes with minimal opportunities to ...introduce diversity. In this report, we disclose the development of a late-stage diversification strategy for the 4- and 5-positions of 4,5,6-trisubstituted indazoles. A regioselective C–H functionalization and subsequent nucleophilic aromatic substitution provide two sequential points of diversification. The synthetic sequence delivers rapid access to an array of 4,5,6-trisubstituted indazoles in only four steps from readily available starting materials.
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8.
Depressive symptoms and frailty St. John, Philip D.; Tyas, Suzanne L.; Montgomery, Patrick R.
International journal of geriatric psychiatry,
June 2013, Volume:
28, Issue:
6
Journal Article
Objectives:
To determine if marital status is associated with depressive symptoms in men and women, and to determine if partner satisfaction is associated with depressive symptoms.
Methods:
...Community-dwelling adults (n = 1751) aged 65 years and older were sampled from a representative population-based registry. Age, sex, education, and marital status were self-reported. Satisfaction with living partner was assessed with an item from the terrible-delightful scale. The Center for Epidemiologic Studies—Depression was used to assess depressive symptoms, with a score of 15 or more indicating depressive symptoms.
Results:
Only 3% of the sample were dissatisfied with their living partner, and those who were dissatisfied with their living partner had higher levels of depressive symptoms. Proportions of men with depressive symptoms were: 20.6% for never married; 19.2% for separated or divorced; 17.3% for widowed; 7.3% for married (satisfied); and 38.1% for married (dissatisfied) (χ2 = 32.98, df = 4, P < 0.001). In women, the results were different: 11.8% for never married; 23.1% for separated or divorced; 15.4% for widowed; 14.4% for married (satisfied); and 41.9% for married (dissatisfied) (χ2 = 18.33, df = 4, P < 0.001). In logistic regression models, a significant interaction term was seen for Marital status x Sex. In stratified models, adjusting for age and education, an effect of marital status was seen in men, but not in women.
Conclusions:
The effects of marriage on depressive symptoms in men and women may be different, with lower levels of depressive symptoms in married men, compared with unmarried men, but similar rates in married women, compared with unmarried women. Dissatisfaction with their partner was uncommon, but highly associated with depressive symptoms.
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