An Enantioselective Synthesis of Cis Perhydroisoquinoline LY235959
作者:Marvin M. Hansen、Carl F. Bertsch、Allen R. Harkness、Bret E. Huff、Darrell R. Hutchison、Vien V. Khau、Michael E. LeTourneau、Michael J. Martinelli、Jerry W. Misner、Barry C. Peterson、John A. Rieck、Kevin A. Sullivan、Ian G. Wright
DOI:10.1021/jo9717649
日期:1998.2.1
of the synthesis include (a) use of a chiral auxiliary controlled asymmetric Diels-Alder reaction to provide the desired absolute and relative stereochemistry at C-4a, C-6, and C-8a, (b) an efficient alkylation of hindered iodide 13 using a novel amide benzophenone imine, (c) oxidative ring opening of the [2.2.2] bicyclic system to simultaneously functionalize the molecule for intramolecular cyclization
(S)-N-Methyl-2-hydroxysuccinimide, easily available from natural (S)-malic acid, supplements the previously introduced (R)-pantolactone as chiralauxiliary for asymmetricDiels-Alderreactions of enoates, but yields products of opposite configuration. Practical large-scale preparations of enantiomer pairs of synthetically important Diels-Alder adducts, including adducts from crotonates, are described
On Baldwin's kinetic barrier against 5-(enol-endo)-exo-trigonal closures: a comparison of ionic and analogous radical reactions, and a new synthesis of cyclopentanones
作者:Derrick L. J. Clive、David R. Cheshire
DOI:10.1039/c39870001520
日期:——
The kineticbarrier that impedes ionic5-(enol-endo)-exo-trigonalclosures does not play such a dominant role in the case of α-oxo radicals (17); these radicals cyclize directly to cyclopentanones in a process that constitutes a synthetic method for converting allylic alcohols (12) into bicyclo[n.3.0]alkanones (19).
Dispiroketals in synthesis (Part 13): Functionalised dispiroketals as new chiral auxiliaries; highly stereoselective diels-alder reactions using a bifunctional, C2- symmetrical chiral auxiliary
作者:Barend C.B. Bezuidenhoudt、Grant H. Castle、Joanna V. Geden、Steven V. Ley
DOI:10.1016/0040-4039(94)85339-8
日期:1994.10
Highly selective, asymmetric, Lewis acid catalysed Diels-Alder reactions are reported with a bifunctional, C2-symmetrical diacrylate derivative obtained from a chiralauxiliary based on dihydroxylated dispiroketals.
A Practical New Chiral Controller for Asymmetric Diels−Alder and Alkylation Reactions
作者:Georgios Sarakinos、E. J. Corey
DOI:10.1021/ol991007s
日期:1999.12.1
prepared from 1,2-epoxycyclohexane by a simple and practical procedure. The acrylate esters of these alcohols undergo BCl3-catalyzed Diels-Alderreactions with a variety of dienes at -78 to -55 degrees C in CH2Cl2 or C7H8 with high dienophile face selectivity (Table 1). The chiral esters so formed are readily cleaved with recovery of the controllers (+)- or (-)-2. Esters of (+)- and (-)-2 can be converted