Catalytic imine–imine cross-coupling reactions

Abstract

We report here efficient catalytic imine-imine cross-coupling reactions based on an umpolung strategy; an imine bearing a 9-fluorenyl moiety on its nitrogen atom, which acted as a nucleophile, reacted with another imine to afford an imine-imine cross-coupling adduct in high yield. Furthermore, a chiral guanidine acted as a chiral catalyst for these coupling reactions, and optically active 1,2-diamines were obtained in high yields with high enantioselectivities.

Natural polarity inverted

“…reactions of carbonyl-containing compounds, and behave as carbon nucleophiles. Several non-enantioselective transformations have previously been reported [10][11][12][13] , and the sole example of a highly enantioselective carbon-carbon (C-C) bond-forming reaction with 2-azaallyl anions was a palladiumcatalysed coupling with carbon electrophiles 14 .…”

Umpolung von Iminen

“…Ein zweiter Weg zum Azaallylanion ist die Deprotonierung α‐C‐H‐azider diarylmethylgeschützter Imine. Kobayshi und Mitarbeiter beschrieben dazu kürzlich eine effiziente Synthese von 1,2‐Diaminen mit C‐H‐aziden Fluorenylaldiminen (20) (Abbildung 5a, S. 1092) 9. Katalytische Mengen Kalium‐2,2,2‐Trifluorethanolat als Base generieren reaktive 2‐Azaallylanionen, die dann mit N‐Diphenylphosphinyl‐geschützten Iminen (21) reagieren.…”

An Organocatalytic Biomimetic Strategy Paves the Way for the Asymmetric Umpolung of Imines

“…[5][6][7][8][9][10] In this Highlight, some of the most recently developed organocatalytic biomimetic concepts for the highly enantioselective and high-yielding umpolung of imines are presented. [5][6][7][8][9][10] In this Highlight, some of the most recently developed organocatalytic biomimetic concepts for the highly enantioselective and high-yielding umpolung of imines are presented.…”

“…Keeping all these facts in mind, it comes as no surprise that some of the leading groups in the field of asymmetric catalysis recently initiated research programs aiming at the development of catalytic asymmetric umpolung strategies that allow for the use of imine precursors as nucleophilic species. [5][6][7][8][9][10] In this Highlight, some of the most recently developed organocatalytic biomimetic concepts for the highly enantioselective and high-yielding umpolung of imines are presented. [6][7][8]10] Before discussing these reports,i ti sn ecessary to have abrief look at one of the well-investigated biosynthesis routes towards chiral a-amino acids 3.…”