73545-15-0Relevant articles and documents
Transannular vs intramolecular insertion reactions of transition metal carbenes: Evaluation of a transannular approach to cyclooctane ring synthesis
Dudones, James D.,Sampson, Paul
, p. 9555 - 9567 (2007/10/03)
The efficacy of closing cyclooctane rings via transannular metal-stabilized carbene insertion reactions within an 11-membered macrocyclic lactone ring was explored. The impact of performing these reactions in a transannular fashion was evaluated via a comparative study of closely analogous intramolecular (but not transannular) processes. Closure of a γ-lactone ring via intramolecular cyclopropanation on a moderately electron-deficient alkene proceeded in good yield under Cu(acac)2 catalysis, whereas analogous transannular cyclopropanation was thwarted by competitive β-hydride migration. In contrast, use of a more electron-rich methoxy-substituted alkene resulted in successful transannular cyclopropanation to afford the desired cyclooctane ring-containing product. (C) 2000 Elsevier Science Ltd.
Cobalt(II)chloride catalysed cleavage of ethers with acyl halides: Scope and mechanism
Iqbal,Srivastava
, p. 3155 - 3170 (2007/10/02)
Cobalt(II) chloride in acetonitrile catalyses the cleavage of a wide variety of ethers with acyl halides under mild conditions to give the corresponding esters in good yields. Acyclic aliphatic ethers are cleaved to the corresponding ester and chlorides whereas the cyclic aliphatic ethers give rise to the ω-chloroesters. The benzyl ethers can be converted to the corresponding esters along with the formation of benzyl chloride and benzyl acetamide. A comparative study for the cleavage of allyl and benzyl ether has revealed that benzyl ether can be selectively cleaved in presence of the allyl ethers. The oxiranes can be cleaved in highly regioselective manner to the corresponding-β-chloroesters. The vinyl ethers undergo sp2-hybridised carbon-oxygen bond cleavage under these conditions. Based on product analysis, a mechanism involving electron transfer followed by O-acylation and S(N)1 or S(N)2 attack by chloride-ion is discussed.
