Domino cyclic olefins

Using a disubstituted aUcyne with appropriately placed alkenes at either side, the domino dienyne metathesis also enables the formation of bicyclic 1,3-dienes where two cyclic olefins are connected by a C-C single bond [20]. Scheme 2.41 depicts such a scenario for the double cyclization of diether 112 to give a virtually quantitative yield of the bisdihydrofuran 113 with Grabbs catalyst 1 [20a,cj. 

Scheme 5.130 Domino hydroformylation-cross aldol addition of cyclic olefins with ketones.

Hu et al. [104] disclosed that the spiro phosphine oxide ligand (/ )-30a is highly efficient for the Pd-catalyzed Heck reaction of cyclic and heterocyclic olefins with aryl triflates. An asymmetric domino Heck cyclization was established using catalyst Pd/(/ )-30a to form fused carbo- and heterocycles with excellent stereoselectivity (Scheme 42) [105]. This method was used in a short synthesis of (-)-martinellic acid, a primary ingredient in traditional eye medicine in South America. 

Scheme 2.73 Domino olefin metathesis/carbonyl olefination furnishing the cyclic enol ether 20S.

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