Organic Copper Reagent Organocuprate
Copper organic compounds as an important reagent in organic synthesis was developed in the late 1960s. It includes two types of compounds, organocopper and organocopper-lithium. Organocopper-lithium reagents are generally denoted as R2CuLi, and these are more stable and active than the well-known organocopper (I) reagents.R2CuLi is a bimetallic complex, and is a commonly used organocuprate reagent in organic synthesis due to its good solubility and activity. One of the useful reactions of organoketolithium reagents is their conjugate addition to unsaturated ketones, whereas the carbonyl groups of non-conjugated ketones do not react under these conditions.
Organocopper-lithium reagents (organocuprate) [R2CuLi], prepared from monovalent copper and two equivalents of organolithium reagents, are highly nucleophilic and are used in 1,4-addition reactions of α,β-unsaturated carbonyl compounds, as well as substitution reactions on sp3 carbons, which are carried out rapidly.
Organocopper reagents are weakly basic, and side reactions such as dehydrogenation are more difficult to occur. In contrast, 1,2-addition occurs preferentially with organolithium reagent alone, and 1,4-addition can be realized by using both reagents.
This reagent is very reactive and can react with carbon atoms with high steric site resistance. The 1,4-addition reaction can be accelerated by using a hard Lewis acid such as TMSCl.
In addition to organolithium reagents, this reagent can also be used in combination with Grignard reagents and organozinc reagents. Especially when used in combination with the latter two, the amount of copper reagent can be reduced to a catalytic amount.
Two equivalents of organolithium reagent are necessary for the smooth running of the reaction, and only one equivalent is actually consumed in the reaction. The mixed organocuprate [R(X)CuLi] (X = alkenyl, -CN, -SR’,-NR’2, PR’2 etc.), can be efficiently utilized for important reactants.
In recent years, a number of asymmetric 1,4-addition reactions have been developed through the use of catalytic amounts of copper-chiral phosphine ligands. Bacteriostatic aspects As can be seen from the results in the figure above, the yeast/zinc fermentation product can exert some inhibitory effect on Propionibacterium acnes at certain concentrations.
Saccharomyces/Zinc fermentation product can exert its unique combination of effects on both acne during puberty as well as scalp problems. As the temperature rises and summer approaches the cortical secretion in the skin increases, the over proliferation of oleophilic fungi further leads to an imbalance in the skin flora, which in turn causes itching, keratinocyte hyperplasia, abnormalities and other problems. Skin irritation itching induces scratching and excessive cleaning, triggering an inflammatory response, accelerating the abnormal differentiation of keratinocytes, which in turn destroys the skin barrier. Increased irritation from environmental exotics at a later stage can further lead to an imbalance in the skin’s micro-ecology.
Sorting out the efficacy characteristics of yeast/zinc fermentation products:
First of all, the role of zinc lies in regulating oil metabolism to a certain extent through topical or oral application, reducing excessive secretion of oil, and thus inhibiting fungal growth and regulating the balance of the flora; at the same time, zinc can also promote cell division and skin healing; in addition, zinc can regulate immune response in the skin cells, improve the immune balance of the skin, and restore the skin barrier function.
With the market’s increasing demand for safety, health and high efficiency, the future application prospects of the yeast/zinc fermentation product from cosmetics and food are promising because of its extensive use in the food field, organic form, safety, high bioavailability and in-depth research in the fields of restoration, oil control, anti-bacterial efficacy and so on.
Translated with DeepL.com (free version)
