The Role of Neighboring Groups in Replacement Reactions. I. Retention of Configuration in the Reaction of Some Dihalides and Acetoxyhalides with Silver Acetate1
A Multicatalyst System for the One‐Pot Desymmetrization/Oxidation of
<i>meso</i>
‐1,2‐Alkane Diols
作者:Christian E. Müller、Radim Hrdina、Raffael C. Wende、Peter R. Schreiner
DOI:10.1002/chem.201100498
日期:2011.5.27
Two is better than one: We demonstrate the viability of an organocatalytic reaction sequence along a short peptide backbone that carries two independent catalytic functionalities, which allow the rapid, one‐pot acylative desymmetrization and oxidation of meso‐alkane‐1,2‐diols to the corresponding acetylated acetoins with good yields and enantioselectivities (see scheme).
Reactions of thallium(I) carboxylates and iodine with alkenes
作者:Richard C. Cambie、Rodney C. Hayward、John L. Roberts、Peter S. Rutledge
DOI:10.1039/p19740001858
日期:——
Treatment of an alkene with a thallium(I) carboxylate and iodine gives the corresponding vic-iodocarboxylate in high yield. The reactions are regiospecific and in conjunction with solvolysis of the products, offer an alternative to the Prévost reaction. Differences in the behaviour of thallium(I) carboxylates and silver carboxylates towards alkenes in the presence of iodine are discussed.
Aerobic Oxidation of Alkenes to Esters of Vicinal Diols with a<i>syn</i>-Configuration Catalyzed by I<sub>2</sub>and the H<sub>5</sub>PV<sub>2</sub>Mo<sub>10</sub>O<sub>40</sub>Polyoxometalate
作者:Ronny Neumann、Olena Branytska
DOI:10.1055/s-2005-917069
日期:——
A new method for the synthesis of vicinal diols fromalkenes has been developed. Reaction of molecular iodine in the presence of a polyoxometalate as oxidation catalyst under aerobic conditions in acetic acid solvent leads to the oxidative iodoacetoxylation of an alkene, i.e. formation of a 1,2-iodoacetate. Further in situ substitution of the iodide by water yields the 1,2-diol monoacetate with a predominantly
The reaction mixtures of 5α-cholest-2-ene with iodine-ammonium cerium(IV) nitrate [CAN(IV)] were converted with potassium hydroxide in methanol-water to give the more hindered 2β,3β-diol in high yield. Cyclohexene and cycloheptene similarly reacted to the corresponding cis-diols in good yield. It was found that this reaction intermediate proceeds to give trans-iodoacetate via trans-iodonitrate. This new synthetic method provided several advantages over the Prevost reaction.