Alpha-hydroxyalkyl heterocycles via chiral allylic boronates: Pd-catalyzed borylation leading to a formal enantioselective isomerization of allylic ether and amine.
An efficient catalytic enantioselective preparation of synthetically useful pyranyl and piperidinyl allylic boronates was achieved via a palladium-catalyzed borylation/isomerization reaction on the corresponding alkenyl triflates. The influence of the base and solvent was found to be crucial on the regio- and enantioselectivity of this reaction. The overall borylation process constitutes a successful example of formal asymmetric isomerization of allylic ether/amine. The resulting allylic boronate reagents add to various aldehydes in a one-pot process to give synthetically useful alpha-hydroxyalkyl derivatives in high stereoselectivity.
Lessard
Stéphanie
S
Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
Peng
Feng
F
Hall
Dennis G
DG
D000473:Alkanes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D002384:Catalysis; D004987:Ethers / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D010165:Palladium / Q000737:chemistry*; D013379:Substrate Specificity; D013696:Temperature
D000473:Alkanes; D000588:Amines; D001897:Boronic Acids; D004987:Ethers; D006571:Heterocyclic Compounds; D010165:Palladium