Dienes, hybridization metathesis

Aluminum—tetradentate ligand catalyst system, in epoxide homopolymerization, 11, 601 Aluminum(I) tetrahedra, synthesis, 9, 262 Aluminum(III)-tin exchange, process, 9, 265 Aluminum-transition metal bonds, characteristics, 9, 264 Amavadine, for alkane carboxylations, 10, 234—235 Ambruticin S, via ring-closing diene metathesis, 11, 218 Amide-allenes, cyclizations, 10, 718 Amide ether complexes, with Zr(IV) and Hf(IV), 4, 783 Amide hybrid ligands, in organometallic synthesis, 1, 64 Amides... 

Polymers with M-C bonds in the main chain where the carbon atom is j/> -hybridized are rare. Such materials have been successfully prepared via acyclic diene metathesis (ADMET) polymerization, which has been used to prepare polycarbostannanes 209 with molecular weights up to 36,000 (PDI = 2.1) and ethylene as the byproduct... 

Next to fused bicyclic systems, the domino dienyne metathesis process can also be applied to the construction of bridged bicyclic dienes. Thus, dienyne 110 bearing differently substituted alkene units to ensure a regiocontrolled cyclization readily afforded the taxosteroid hybrid compound 111 without competing cyclopentene formation in the presence of the Grubbs second-generation catalyst 2 (Scheme 2.40) [19]. 

A similar strategy has been used by Kotha to synthesize naphthoquinones and anthraquinones containing amino acid functionahties [45]. In this case, the racemic amino acid alkyne hybrid 116 was treated with ethylene in an enyne metathesis fashion to yield the diene 117, which was then subjected to a Diels-Alder reaction with 2,3-dimethylbenzoquinone 118 (as shown in Scheme 17.23), to afford... 

---