A facile method for deblocking of dithianes is described. Diacetoxyiodobenzene was used as a cheaper variant of bis(trifluoroacetoxy)iodobenzene for the regeneration of carbonyl compounds from dithianes.
products, and biologically active compounds showcase the robustness and functional‐group tolerance of the reaction. The key to the success of the reaction could be the possible formation of the strong Si−O bond via a Brook‐type rearrangement. Given its simplicity and efficiency, this ligation has the potential to unfold new applications in the areas of medicinal chemistry and chemical biology.
The spirocyclization of straingt-chain triketo-intermediates, similar to possible biogenetic precursors of histrionicotoxin, is shown to be stereoselective, generating the non-natural configuration at C-2. Aiming at an sp2-center in this position, triketo-brassylic ester was treated with ammonia at room temperature and was shown to cleanly and efficiently yield a spiroketone.
When Ethyl Is Infinitely Different from Methyl: Double Addition of Lithiated Dithianes to Aromatic Carboxylates Revisited
作者:Roman A. Valiulin、Rudresha Kottani、Andrei G. Kutateladze
DOI:10.1021/jo060780f
日期:2006.6.1
benzoate does not produce the expected product of double addition, α,α-bis(alkyldithianyl) benzyl alcohol, for alkyls larger than methyl. Instead, the first step intermediate, i.e. 2-benzoylated dithiane, undergoes an electron-transfer reduction by the second molecule of the dithianyl anion. This reduction is followed by the ring-opening mesolytic fragmentation of the dithiane ring in the ketyl anion radical
Heteropoly Acids as Heterogeneous Catalysts for Thioacetalization and Transthioacetalization Reactions
作者:Habib Firouzabadi、Nasser Iranpoor、Kamal Amani
DOI:10.1055/s-2002-19300
日期:——
Heteropoly acids are effective solid catalysts for the thioacetalization of carbonyl compounds. Tungstophosphoric acid (H 3 PW 1 2 O 4 0 ), was found to be an effective and a highly selective catalyst for the thioacetalization of aldehydes, ketones and for the transthioacetalization of acetals, acylals and O,S-acetals which proceeded in excellent yields in the absence of solvent. The catalyst has also been
Depsidone synthesis. Part 16. Benzophenone–grisa-3′,5′-diene-2′,3-dione–depsidone interconversion: a new theory of depsidone biosynthesis
作者:Tony Sala、Melvyn V. Sargent
DOI:10.1039/p19810000855
日期:——
The synthesis of a number of grisa-3′,5′-diene-2′,3-diones by oxidative coupling of substituted 2,2′-dihydroxy-4-methoxybenzophenones is described. The rearrangement of these grisadienediones to depsidones under basic, acidic, and thermal conditions is described and the mechanisms of these reactions are discussed. It is proposed that depsidone biosynthesis involves the oxidative coupling of benzophenones