Domino metathesis reactions substitution

Perhydrofuro[3,4-.i]pyrans can be prepared via a regioselective domino metathesis reaction of ally I- and propargyl-substituted oxanorbornenic esters, 129. The resulting /ra s-fmed perhydrofuro[3,4-/ ]pyran derivatives are formed in high yields <2000TL9777>. 

The most important ruthenium-catalyzed domino process is based on a metathesis reaction. Nonetheless, a few other ruthenium-catalyzed processes have been employed for the synthesis of substituted 3,y-unsaturated ketones, as well as unsaturated y-lactams and allylic amines. 

Plumet et al. described domino metathesis of propargyl (2-endo-7-oxanorborn-5-enyl) ethers 62a-62c with allyl acetate in the presence of Grubbs ruthenium catalyst Ic (Scheme 22). The reaction proceeds stereoselectively to produce substituted m-fused bicyclic ethers 63a-63c. In a similar manner, indolizidinone derivative 64 is obtained from compound 62d instead of pyrrolizidine derivative 63d. ... 

Domino metathesis of siloxy-tethered dienynes offers attractive opportunities for the synthesis of stereochemically defined 1,3-dienes after desilylation [21]. These reactions also allow the efficient preparation of highly substituted cycloolefins, which is illustrated in Scheme 2.43 [21b,c]. Selective double cydization of silaketal 118 via initiation at the monosubstituted alkene led to a fused 6/7-bicychc product which was subsequently desilylated to afford the triol 119 in high overall yield. 

In our previous book on domino reactions [4h], we have classified domino reactions according to the mechanism of the different steps. This organizing principal will also be used in this book, and you will find chapters about transition metal catalysis including carbonylation, metathesis and CH-activation, nucleophiHc substitutions, radical reactions, pericyclic reactions, Michael reactions, aldol reactions, oxidations, and reductions. 

Metathesis events and substitution reactions can be readily combined in attractive domino processes. Thus, a dual catalysis with palladium and ruthenium complexes... 

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