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An efficient rhodium(II)-catalyzed three-component reaction of 3-diazooxindoles, indoles and formalin was reported. With this transformation, a series of 3-(hydroxymethyl)-3-indol-3′-yloxindoles were easily afforded in good to excellent yields. The resulted 3-(hydroxymethyl)-3-indol-3′-yloxindole could be easily converted to the key intermediate for the total synthesis of gliocladin C. [ABSTRACT FROM AUTHOR]

Abstract: The kodaistatins A and C (5a,b) inhibit a step in glucose-metabolism at ∼100 nM concentrations. This makes them potential ‘leads’ in the therapy of diabetes. We elucidated the (S)-configuration of the side-chain stereocenter of kodaistatin A by ozonolysis/reduction. The 13C NMR shifts of kodaistatin A model cis-11 suggest that the diol moiety in the dihydroxycyclopentanone core of kodaistatin is trans-configured. This model was prepared from the Feringa lactone (21) and (S)-2-methylbutanal (27) in 23 steps (14 steps in the longest linear sequence). We employed the same strategy for the simplified kodaistatin A model iso-cis-12, which resulted from the same substrates in 11 steps (6 steps in the longest linear sequence). The cyclopentenone cores of both targets stemmed from a C4+C1 approach. The C4 components were masked ‘tartaric ketones’ (16a,b) and a masked ‘tartaric aldehyde’ (18), respectively. The C1 components were the lithium-derivatives of the side-chain bearing phosphonates 19 and 22, respectively. The desired acylation/deprotonation/Horner–Wadsworth–Emmons tandem reaction succeeded in a single operation with the ‘tartaric aldehyde’ 18 but required partly or exclusively additional operations when we incorporated the ‘tartaric ketones’ 16a or 16b, respectively. The ‘tartaric ketones’ 16a,b contained an α-siloxyethyl substituent. It is noteworthy that it had to be introduced by adding the benzyltrimethylammonium enolate of lactone 18 to acetaldehyde because the lithium enolate of this lactone fragmented by an acetone-releasing β-elimination. [Copyright &y& Elsevier]

Abstract: In this article we describe a new accessible methodology for the synthesis of isobenzofuran-1(3H)-ones. In this process we exploited an effective, economic, useful and environmentally benign K2CO3 catalyzed, solvent-free one-pot tandem aldol-lactonization reaction between active methylene compounds and methyl 2-carboxy benzaldehyde. A particularly simple work-up and purification procedure are additional advantages addressed to a general green chemistry approach to this important class of heterocyclic compounds. [Copyright &y& Elsevier]

Abstract: The stereochemical course in the addition of lithiated benzylcyanide and propionitrile to aromatic Schiff bases, as well as of the subsequent alkylation reaction has been investigated. The stereochemical ratios in the condensation reaction are proved to result from the intermediacy of a prochiral carbanionic intermediate, produced by a fast proton shift in the initially formed azanion. Subsequent one-pot alkylation reaction with a variety of electrophiles leads in high to moderate yields to diastereoselective formation of a second carbon–carbon bond at the same carbon center. Diastereoselectivity in alkylation, which varies from outstanding to high and poor is rationalized in terms of open-chain, product-like or reactant-like transition state models. [Copyright &y& Elsevier]

An efficient TiCl4–Bu3N—(cat. TMSCl)-promoted aldol addition between ketones and ketones or aldehydes was performed. This environmentally benign method is advantageous from a green chemical viewpoint with regard to yield, substrates variation, reagent availability, and simple procedures. This method was applied to a short step formal synthesis of (R)-muscone, a natural macrocyclic musk. [Copyright &y& Elsevier]