A Highly Efficient Synthetic Protocol for Tetrahydropyranylation/Depyranylation of Alcohols and Phenols
作者:Abu T. Khan、Subrata Ghosh、Lokman H. Choudhury
DOI:10.1002/ejoc.200500400
日期:2005.11
Bismuth(III) nitrate pentahydrate [Bi(NO3)3·5H2O] is found to be an effective catalyst for both tetrahydropyranylation and depyranylation of alcohols and phenols. Some of the major advantages of this protocol are: non-aqueous workup, good yields, the involvement of a less-expensive and nontoxic catalyst, and compatibility in the presence of a large number of other protecting groups. Notably, isopropylidene
Nerol, acyclic monoterpene alcohol, has been stereoselectively synthesized using as an intermediate the unsaturated hydroxylic acid VI, in which the carboxyl and the hydroxymethyl groups are evidently in the cis-relation.
Selective Synthesis of 1,3-Dienic Terpenes in a β-Form through Regioselective 1,4-Elimination of Allylic Ethers
作者:Junzo Otera、Yoshihisa Niibo、Kazuhiro Okuda
DOI:10.1246/cl.1986.1829
日期:1986.11.5
γ-Methyl-substituted allylicethers proved to be converted into β-substituted dienes exclusively on treatment with t-BuOK in refluxing THF or cyclohexane.
Studies on Chiral Organosulfur Compounds. V. Palladium-Catalyzed Intramolecular Asymmetric Metallo-Ene Reactions via Chiral Allylic Sulfinate-Sulfone Rearrangements.
作者:Kunio HIROI、Kazushige HIRASAWA
DOI:10.1248/cpb.42.1036
日期:——
A palladium-catalyzed intramolecular asymmetric metallo-ene reaction was accomplished using a chiral allylic sulfone (prepared by thermal rearrangement of an optically active allylic sulfinate) as an enophile. The stereoselectivity of the reaction was determined by high-performance liquid chromatography with a chiral column. A plausible mechanistic pathway for this asymmetric cyclization is presented.