Bicyclic oxygen heterocycles from γ,δ-unsaturated alcohols: synthetic targets inspired by blepharocalyxin D.

trans-2,8-Dioxabicyclodecanes were prepared in high yield with the creation of up to three stereocenters in a single pot by the acid-mediated reaction of γ,δ-unsaturated alcohols with aldehydes (see scheme, Bn=benzyl). This versatile reaction enables the stereoselective introduction of substituents at the C3, C4, C7, and C9 positions of the bicyclic framework.

Chemoenzymatic and enantiodivergent routes to 1,2-ring-fused bicyclo[2.2.2]octane and related tricyclic frameworks.

New and simple protocols are described for the conversion of the enzymatically-derived and enantiomerically pure cis-1,2-dihydrocatechol (X = I) and its 6-methylated derivative into either antipodal form of compounds embodying the tricyclic frameworks of terpenoids . Key steps include intramolecular Diels-Alder (IMDA) and (in some cases) singlet or triplet-based photochemical processes.

Intramolecular Prins cyclisations for the stereoselective synthesis of bicyclic tetrahydropyrans.

Methyl (4E,7R)-7-hydroxyoctanoate was prepared in 71% yield from ethyl (R)-3-hydroxybutanoate and on reaction with a series of aldehydes in the presence of TMSOTf gave bicyclic oxygen heterocycles in good yields and with the creation of three new stereogenic centres in a single pot.

Total synthesis of the marine natural product (-)-clavosolide A.

[Structure: see text] The total synthesis of the marine metabolite clavosolide A is reported which confirms the structure and absolute configuration of the natural product as the symmetrical diolide glycosylated by permethylated D-xylose moieties, 2.

Total synthesis of a diastereomer of the marine natural product clavosolide A.

The first total synthesis of the reported structure of the sponge metabolite clavosolide A is described using a Prins cyclisation to assemble the tetrahydropyran core followed by manipulation of the side-chain, dimerisation and finally glycosidation.