Highly enantioselective syntheses of heterocycles via intramolecular Ir-catalyzed allylic amination and etherification.
[reaction: see text] Enantioselective Ir-catalyzed intramolecular allylic aminations and etherifications are described. Up to 97% ee was achieved using catalysts prepared by in situ activation of mixtures of phosphorus amidites and [Ir(COD)Cl]2. Sequential aminations of bis-allylic carbonates, involving an inter- followed by an intramolecular reaction, gave trans-N-benzyl-2,5-divinylpyrrolidine and trans-N-benzyl-2,6-divinylpiperidine with > or = 99% ee. New phosphorus amidites as well as improved conditions for intermolecular aminations are reported.
Welter
Carolin
C
Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
Dahnz
Axel
A
Brunner
Bernhard
B
Streiff
Stephane
S
Dübon
Pierre
P
Helmchen
Günter
G