Evans auxiliary-based asymmetric synthesis
E634404
Evans auxiliary-based asymmetric synthesis is a widely influential chiral auxiliary strategy developed by David A. Evans that enables highly stereoselective construction of complex molecules in organic synthesis.
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
asymmetric synthesis strategy
ⓘ
chiral auxiliary methodology ⓘ stereoselective synthesis method ⓘ |
| advantage |
auxiliary can be removed after stereocenter formation
ⓘ
auxiliary can often be recovered and reused ⓘ |
| appliedIn |
complex molecule construction
ⓘ
pharmaceutical synthesis ⓘ total synthesis of natural products ⓘ |
| basedOn | chiral N-acyl oxazolidinone auxiliaries ⓘ |
| contrastsWith | catalytic asymmetric synthesis ⓘ |
| controls | relative configuration of newly formed stereocenters ⓘ |
| developedBy | David A. Evans NERFINISHED ⓘ |
| enables | highly stereoselective construction of complex molecules ⓘ |
| field |
organic chemistry
ⓘ
synthetic organic chemistry ⓘ |
| followedBy | auxiliary cleavage to reveal enantiomerically enriched products ⓘ |
| historicalImpact | popularized chiral auxiliary approach in asymmetric synthesis ⓘ |
| influenced | development of other chiral auxiliary systems ⓘ |
| involves |
diastereoselective bond formation
ⓘ
enolization under basic conditions ⓘ formation of N-acyl imides ⓘ |
| keyIntermediate | chiral metal enolate ⓘ |
| keyTransformation | diastereoselective Michael addition ⓘ |
| keyTransformation |
diastereoselective acylation
ⓘ
diastereoselective conjugate addition ⓘ |
| keyTransformation | diastereoselective aldol reaction ⓘ |
| keyTransformation | diastereoselective enolate alkylation ⓘ |
| namedAfter | David A. Evans NERFINISHED ⓘ |
| optimizationParameter |
choice of base and metal counterion
ⓘ
temperature control for stereoselectivity ⓘ |
| provides |
high diastereoselectivity
ⓘ
predictable stereochemical outcome ⓘ |
| reliesOn |
chelation-controlled transition states
ⓘ
diastereofacial differentiation of enolates ⓘ |
| requires | stoichiometric amount of chiral auxiliary ⓘ |
| stereochemicalOutcome | products with high enantiomeric excess after auxiliary removal ⓘ |
| stereocontrolOrigin | chiral environment of the oxazolidinone ring ⓘ |
| strategyType | substrate-controlled stereoselective synthesis ⓘ |
| timePeriodOfDevelopment |
1980s
ⓘ
late 1970s ⓘ |
| typicalAuxiliaryBackbone | oxazolidinone derived from amino alcohols ⓘ |
| typicalMetalCounterion |
boron
ⓘ
lithium ⓘ titanium ⓘ |
| typicalSubstrateClass | chiral N-acyl oxazolidinones ⓘ |
| usedFor |
construction of contiguous stereocenters
ⓘ
construction of quaternary stereocenters ⓘ |
| uses |
Evans chiral auxiliary
NERFINISHED
ⓘ
N-acyloxazolidinone chiral auxiliaries ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.