1,3 enynes/1,3 diynes

Other conjugated systems, including trienes, enynes, diynes, and so on, have been studied much less but behave similarly. 1,4 Addition to enynes is an important way of making allenes ... 

Stoichiometric bicydization of enynes, diynes, and dienes by cyclic carbozirconation... 

Transition metal-catalyzed carbocycUzation reactions of tethered diene, enyne, diyne, and vinylallene derivatives represent an important class of transformations in synthetic organic chemistry. This may be attributed to the abihty to significantly increase molecular complexity through the highly selective combination of acyclic components, thereby facilitating the synthesis of complex polycychc products. Recently, rhodium-catalyzed carbocyclization reactions have attracted significant attention due to their immense synthetic versatility and the unique selectivities observed over a range of different transformations. This chapter provides an account of recent developments in rhodium-catalyzed [4-1-2] and [4-i-2-t2] carbocyclization reactions. 

For this selective addition, the best catalyst precursors were Ru(methallyl)2(dppe) 1 and Ru(methallyl)2(dppb) 2. The choice of the appropriate complex depended on the steric demand of both the alkyne and the carboxylic acid. A large variety of carboxylic acids and alkynes have been used, including N-protected amino acids, a-hydroxy acids, and functionalized alkynes such as enynes, diynes and propargylic ethers [21-23] (Scheme 10.4). The addition took place under mild conditions and carboxylic adds of... 

Zn (ZnBr2-K), H20, MeOH, THF (enyne, diyne, propargylic alcohol)... 

Zn, BrCH2CH2Br, CuBr, LiBr, EtOH (propargylic and homopropargylic alcohol and amine, propargyhc ether, enyne, diyne)... 

Co2Rh2(CO)i2] and [Co3Rh(CO)i2] catalyze the hydrosilation of isoprene, cyclohexanone, cyclohexenone, and 1-alkynes, the regioseleetive inter- or intramolecular (Eq. 5) silylformylation of alkynes and 1-alkynals, and the silylcarbo-cyclization of enynes, diynes, and alkynals. These synthetically important reactions have been reviewed recently. 

Intermolecular enyne-diyne cross-benzannulation offers a convenient synthetic method for cyclophanes. The cyclic enyne 213 reacted smoothly with 12-carbon-tethered cyclic diyne 214, and the meto-cyclophane having both 15- and 16-membered rings 215 was prepared in high yield (72 %) [65],... 

Scheme 1.3 Zirconocene-mediated cyclization of enyne, diyne, or diene...

Gevorgyan, V., Quan, LG. and Yamamoto, Y. (1998) Regiospecific synthesis of polysubstituted phenols via the palladium-catalyzed enyne-diyne [4-1-2] cross-benzannulation pathway. Journal of Organic Chemistry, 63(4), 1244-1247. 

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