Organic Derivatives of Group I and II Metals

The organic derivatives of lithium and magnesium are the most important of the group I and II organometallics. The metals in these two groups are the most electropositive of the elements. The polarity of the metal-carbon bond is such as to place high electron density on carbon. This electronic distribution is responsible for the strong nucleophilicity and basicity that characterize these compounds. As... 

In a difference from the above, the majority of metal halides of secondary subgroups of Group I, II, and VII and lanthanides are low-soluble in the examined solvents, so synthesis of their complexes is carried out in comparatively high-polar solvents (water, alcohols, and aqueous-alcohol mixtures). To carry out syntheses in water, the corresponding conditions, necessary to obtaining soluble derivatives of organic compounds (for example, halide hydrates of amines or N-containing hetero-... 

In Scheme 5.46, the syntheses of different macrocyclic natural products classified as alkaloids are summarized. The rich variety of biological activities associated with both plant-derived and animal-derived alkaloids has stimulated many organic synthetic groups. The main problem from a metathesis point of view is the abihty of the nitrogen to coordinate to metal-alkyhdene complexes and to interfere unpro-ductively with the catal)rtic activity. In the examples summarized herein, the use of [Ru]-I, [Ru]-II, and [Ru]-V has proven to be effective. Consequently, (—)-sarain A (189) (Equation 1, Scheme 5.46), isolated from sponge Reniera sarai [81] ircinal... 

There are several excellent photosensitizers one of them is [Ru(bpy)3]2+ [6]. There are two optical isomers in this complex one is A [Ru(bpy)3]2+ and the other is A-[Ru(bpy)3]2 +, as shown in Scheme 1. Thus one can expect to perform the stereoselective electron transfer reaction with A- and A-[Ru(bpy)3]2 +. Unfortunately, however, the racemization of [Ru(bpy)3]2+ is induced photochemically [7]. The reasonable way to suppress the photoracemiza-tion of this complex is to introduce the optically active organic functional group into the transition metal complexes, as will be discussed in Sec. II.B. The other photosensitizer that is useful for the photoinduced electron transfer reaction is the copper(I) complexes with 1,10-phenanthroline and their derivatives [8,9]. Zinc(II) porphyrin is also an excellent photosensitizer for photoinduced electron transfer reaction [10]. In these complexes, molecular chirality does not exist, unlike in [Ru(bpy)3]2 +. Thus one must introduce some chiral functional group into these compounds, to use these complexes as chiral photosensitizers. 

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