Dictating Thermodynamic Control through Tethering: Applications to Stereoselective Bis-Spiroketal Synthesis
Austin H Asari1, Paul E Floreancig1
1Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
Abstract:
Approaches to stereocontrol that invoke thermodynamic control fail when two or more potential products are energetically similar, but rational structural perturbations can be employed to break the energetic degeneracy and provide selective transformations. This manuscript illustrates that tethering is an effective approach for the stereoselective construction of bis-spiroketals with thermodynamically similar stereoisomers, providing a new approach to set remote stereocenters and prepare complex structures that have not previously been accessed stereoselectively.
More Related Videos
07:36Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
06:31Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators
Published on: November 27, 2015
Related Concept Videos
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Cycloaddition Reactions: MO Requirements for Thermal Activation
