Timo V. Ovaska

TL;DR: An efficient and highly stereoselective total synthesis of the natural product (+/-)-welwitindolinone A isonitrile is described, with described strategies for construction of the spiro-oxinole include a SmI2-LiCl mediated reductive cyclization and a novel anionic cyclization that simultaneously constructs theSpiro-oxindole and vinyl isonanticle moieties.

TL;DR: In this article, it was shown that the cyclization of 5-hexen-1-yl radicals proceeds via a transition state that resembles a chair cyclohexane in which substituents preferentially occupy pseudoequatorial positions.

TL;DR: In this paper, the scope and limitations of cyclization reactions involving acetylenic alkyllithiums, which were prepared at -78 o C by lithium-iodine exchange between the corresponding iodide and tert-butyellithium in a solution of n-pentane-diethyl ether (3:2 by volume), have been investigated.

TL;DR: The complete carbon skeleton of welwitindolinone A isonitrile has been prepared by using a [2+2] cycloaddition to establish the bicyclo[4.2.4.0]octane core and a SmI2-mediated intramolecular reductive cyclization between an enone and an aryl isocyanate to stereoselectively install the spiro-oxindole.

TL;DR: Appropriately substituted nonracemic allyl alcohols, readily prepared from the corresponding enones by application of the CBS methodology, were converted to optically active cycloheptenone derivatives with almost complete transfer of chirality via an efficient "one-pot", cycloisomerization/Claisen rearrangement process.