Oxygenated cembranes

One of the most typical photochemical reactions, C=C double bond isomerization, may have a synthetic value. Thus, the highly oxygenated cembrane 17-deoxyprovidencin 20 has been built by joining two separately prepared building blocks and further elaboration of the macrocycle 21 via a Z-selective ring closing metathesis. The Z C=C bond isomerizes by irradiation with Pyrex-filtered light that... 

Review of oxygenated 2,11-cyclized marine cembranoids, tri- and tetracyclic bioactive 0-heterocycles with cembrane skeleton 98H(49)531. 

Lewis-acid promoted cyclizations of allylic stannanes have been successfully employed to prepare macrocyclic compounds. An enantioenriched a-oxygenated allylic stannane led to a 14-membered cembrane precursor in high yield with excellent diastereoselectivity (Eq. 64) [80]. 

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