Hydro-alkoxy-addition

Addition of Alcohols and Phenols Hydro-alkoxy-addition... 

Alkoxy)diborons, alkyne additions, 10, 727-728 Alkoxy-hydro carbonylation, in ionic liquids, 1, 863 Alkoxy ketones, asymmetric hydrogenation, 10, 47 Alkoxylation... 

Addition reactions of the Si-Si bonds across carbon-carbon triple bonds have been most extensively studied since the 1970s by means of palladium catalysts. In the early reports, palladium complexes bearing tertiary phosphine ligands, mostly PPh3, were exclusively employed as effective catalysts, enabling the alkyne bis-silylation with activated disilanes, i.e., disilanes with electronegative elements on the silicon atoms such as hydro [36], fluoro [37], chloro [38], and alkoxy-disilanes [39,40] and those with cyclic structure (Scheme 4) [41-44]. The bis-silylation reactions could be successfully applied to terminal alkynes and acetylenedicarboxylates to give (Z)-l,2-bis(silyl)alkenes, which are otherwise difficult to synthesize. 

The approach to cycloheptadienes via thermal Cope rearrangement of an appropriate 1,2-divinylcyclopropane is an attractive one, limited only by the availability of the latter. A number of groups of workers have now described efficient routes to divinylcyclopropanes based on addition of 2-vinylcyclopropyl-lithium or -cuprates to 3-alkoxy- or 3-halogeno-cycloalk-2-enones (Scheme 30), and extensions of these studies to the total synthesis of the biologically important natural hydro-azulene systems are anticipated. 

---