A regioselective annulation of butenolides. The total synthesis of (±) confertifolin

Formation of new 5,11b-bridged isoindolo

[formula: see text] The tandem Pummerer/pi-aromatic cyclization of alpha-acyliminium ion, leading efficiently in "one pot" to thiopoxyareno-bridged isoindoloisoquinolinone incorporating the arylthio group, has been demonstrated for the first time. During this sequence the angular hydroxylated isoindoloisoquinolinone, resulting from the Pummerer-type cyclization, was also obtained.

Base-Induced Rearrangement of Perhydronaphthalene-1,4-diol Monosulfonate Esters to 11-Oxatricyclo[5.3.1.0(2,6)]undecanes. Total Synthesis of Furanether B

It is observed that mesylate 1 on exposure to Li(Ot-Bu)(3)AlH in refluxing toluene rearranges selectively to the 11-oxatricyclo[5.3.1.0(2,6)]undecane derivative 3. A similar rearrangement, leading to a bridged tricyclic ether (14 --> 5), has been used as the key to the total synthesis of furanether B (4), a naturally occurring lactarane sesquiterpene, with the readily available ketone 8 as the starting material. Completion of the synthesis of the natural product is accomplished by an annulation method based on a Pummerer-induced cyclization reaction.