Photobicyclization 2 + 2 photocycloaddition

Besides the l-(but-3-enyl)allyl alcohols discussed above, 2- and 3-(pent-4-enyl)allyl alcohols also undergo clean photobicyclization in the presence of copper trifluoromethanesulfonate as catalyst. However, no intramolecular photocycloaddition product could be isolated from irradiation of a homologous 2-(hex-5-enyl)allyl alcohol.8... 

That both C=C bonds participating in 2n + 2n photocycloadditions can be acyclic is evident from the photobicyclization reactions of simple diallyl ethers that deliver bicyclic tetrahydrofurans (eq 20). In conjunction with ruthenium(IV) oxide-catalyzed oxidation by sodium periodate, these CuOTf-catalyzed photo-bicyclizations provide a synthetic route to butyrolactones from diallyl ethers (eq 20), The synthetic method is applicable to the construction of multicyclic tetrahydrofurans and butyrolactones from diallyl ethers (eq 21 and eq 22) as well as from homoallyl vinyl ethers (eq 23). ... 

Copper(I) triflate-catalyzed photobicyclization of p and y-(4-pentenyl)allyl alcohols provides a synthetic route to various multicyclic carbon networks in excellent yields (eq 29-31). The reaction was exploited in a total synthesis of the panasin-sene sesquiterpenes (eq 32) It is especially noteworthy in this regard that attempted synthesis of a key tricyclic ketone intermediate for the panasinsenes by the well-known photocycloaddition of isobutene to an enone failed to provide any of the requisite cyclobutyl ketone (eq 33) ... 

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See also in sourсe #XX -- [ , , ]

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