Chemoenzymatic Synthesis of <i>trans</i>-Tetrahydrofuran Cores of Annonaceous Acetogenins from Bromobenzene
作者:Juan Carlos Ramos、Margarita Brovetto、Gustavo A. Seoane
DOI:10.1021/ol400650v
日期:2013.4.19
Two types of trans-THF cores, present in acetogenins, have been synthesized by an intramolecular iodoetherification reaction. The starting alkenol was obtained in a few steps from a chiral cis-diol resulting from microbial oxidation of bromobenzene. The cyclization gave complete stereoselectivity for trans-THF cores with either (S,S) or (R,R) configurations at the THF chiral carbons.
Chemoenzymatic synthesis of a mixed phosphine–phosphine oxide catalyst and its application to asymmetric allylation of aldehydes and hydrogenation of alkenes
作者:Derek R. Boyd、Mark Bell、Katherine S. Dunne、Brian Kelly、Paul J. Stevenson、John F. Malone、Christopher C. R. Allen
DOI:10.1039/c1ob06599h
日期:——
coupling and a novel room temperature Arbuzov [2,3]-sigmatropic rearrangement of an allylic diphenylphosphinite. Allylation of aromatic aldehydes were catalysed by the Lewis basic organocatalyst giving homoallylicalcohols in up to 57% ee. This compound also functioned as a ligand for rhodium-catalysed asymmetric hydrogenation of acetamidoacrylate giving reduction products with ee values of up to 84%.
A study of substrate specificity of toluene dioxygenase in processing aromatic compounds containing benzylic and/or remote chiral centers
作者:Vu P. Bui、Trond Vidar Hansen、Yngve Stenstrøm、Tomas Hudlicky、Douglas W. Ribbons
DOI:10.1039/b006545p
日期:——
A series of substituted arenes containing remote chiral centers were screened as substrates for toluene dioxygenase (TDO). The absolute stereochemistry of the new metabolites was determined by chemical and spectroscopic correlation with synthetic standards. There was no evidence for kinetic resolution; enantiomers were indiscriminately processed by the enzyme to diastereomeric pairs, which were separable
Toluene dioxygenase-mediated oxidation of aromatic substrates with remote chiral centers
作者:Vu Bui、Trond Vidar Hansen、Yngve Stenstrøm、Douglas W. Ribbons、Tomas Hudlicky
DOI:10.1039/b002143l
日期:——
Several aromatic substrates containing remote chiral centers were subjected to toluene and naphthalene dioxygenase expressed in blocked mutants and recombinant organisms yielding cis-diol metabolites with little or no kinetic resolution.
Reaction cascades based on squarate esters. 1,3-Dioxolane as a chaperone functional group for lithium ions
作者:Leo A. Paquette、Lung Huang Kuo、Julien Doyon
DOI:10.1016/0040-4020(96)00644-8
日期:1996.8
first-stage addition leads to a chromatographically separable mixture of diastereomeric keto alcohols, which are formed in a ratio approximating 1:1. Separate reaction of these intermediates with the second cycloalkenyl anion initiates a cascade of chemical steps. The consequences of the second-stage stereoselectivity are profound in dictating the manner in which the polycyclic end products are formed