Heterobimetallic gallium complexes

The higher selectivity of these catalysts may be attributed to simultaneous activation of both the nucleophile and electrophile within an asymmetric framework. The heterobimetallic gallium complex (12.138) also functions by binding to both... 

Without question, the most significant advance in the use of sulfur-centered nucleophiles was made by Shibasaki, who discovered that 10 mol% of a novel gallium-lithium-bis(binaphthoxide) complex 5 could catalyze the addition of tert-butylthiol to various cyclic and acyclic meso-epoxides with excellent enantioselectiv-ities and in good yields (Scheme 7.11) [21], This work builds on Shibasaki s broader studies of heterobimetallic complexes, in which dual activation of both the electrophile and the nucleophile is invoked [22]. This method has been applied to an efficient asymmetric synthesis of the prostaglandin core through an oxidation/ elimination sequence (Scheme 7.12). 

Metallotropic rearrangement, in mercury tri-azenide complexes, 30 41 Metals, see also Heterobimetallics specific element Transition metal complex alkoxides, 15 159-297 of actinides, 15 290-293 of alkali metals, 15 260-263 of alkaline earths, 15 264-266 of aluminium, 15 266-272 of beryllium, 15 264-266 double type, 15 293-294 of gallium, 15 266-272 of lanthanides, 15 290-293 of magnesium, 15 264-266 properties of, 15 260 of transition metals, 15 272-290 trialkylsilyloxides, 15 295-297 of zinc, 15 264-266... 

Third heterobimetallic asymmetric catalyst reported by Shibasaki et al., gallium-sodium-BINOL complex (GaSB) 26 and indium-potassium-BINOL complex (InPB), are also rather effective catalysts for asymmetric Michael reactions, and GaSB was better than InPB in terms of enantioselectivity. The GaSB catalyst was prepared from GaCl3, NaO Bu (4 mol equiv. to... 

F-block metal complexes with bonds with another metal are extremely rare. The Arnold group presented in 2007 the first synthesis of a heterobimetallic REM NHC complex [eqn (6.4)]. A salt elimination reaction between [a gallium diyl and neodymium dimer [(NHC)Nd(N[SiMe3]2)(p-I)] 47 in THE yielded [(NHC)Nd(N[SiMe3]2)(THF)(Ga[NArCH]2)] 48 at room temperature. This compound was stable both in solid state and in solution for several months and decomposed only upon heating to 100 °C for 16 h. 

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