A Novel Asymmetric Azaspirocyclisation Using a Morita-Baylis-Hillman-Type Reaction (original) (raw)

A General Asymmetric Formal Synthesis of Aza-Baylis-Hillman Type Products under Bifunctional Catalysis

Chemistry (Weinheim an der Bergstrasse, Germany), 2017

A new organocatalytic strategy for the synthesis of enantioenriched aza-Baylis-Hillman type products via a frustrated vinylogous reaction is presented. This process proceeds under mild conditions with good yields, completed Z/E selectivity and excellent enantioselectivities. Moreover, easy derivatizations of the final products led to important building blocks of organic synthesis such as 1,3-aminoalcohols and Lewis base catalysts.

Enantioselective synthesis of angularly substituted 1-azabicyclic ring systems: dynamic kinetic resolution using aza-Cope rearrangements

Journal of the American Chemical Society, 2010

A useful enantioselective synthesis of angularly substituted 1-azabicyclic molecules that delivers the bicyclic amine products in good yield and 99% ee is reported. Angularly substituted cis-octahydrocyclopenta[b]pyrroles, cis-octahydroindoles, cis-decahydrocyclohepta[b]pyrroles, and cis-octahydrocyclopenta[b]pyridine are formed in good yields and 99% ee exclusively as the cis stereoisomers. Decahydroquinolines are generated as mixtures of cis and trans stereoisomers in similarly high ee. The starting materials for this cascade transformation are assembled in five steps from cycloalkanones and enantiomerically pure (R)-2-phenyl-3-butenamine. This enantioselective synthesis introduces a new strategy for dynamic kinetic resolution in which a rapid tautomeric equilibration of diastereomeric iminium cations is combined with a diastereoselective sigmatropic rearrangement.

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