Carbocycles via enantioselective inter- and intramolecular iridium-catalysed allylic alkylations

Abstract

Carbocycles with > 90% ee were prepared via Ir-catalysed asymmetric allylic alkylation/ring closing metathesis sequences or enantioselective Ir-catalysed intramolecular allylic alkylations.

Transition metals in organic synthesis: Highlights for the year 2005

“…(75)) [633]. Iridium catalyzed asymmetric inter-and intramolecular allylic alkylations using allylic carbonates [634]. Iridium catalyzed regio-and enantioselective allylic alkylations of ketone enolates was also reported [635].…”

Metal‐Catalyzed Enantioselective Allylation in Asymmetric Synthesis

“…[279] Cyclic amines 298 can be prepared in an analogous manner by the reaction of aminoallyl acetate 296 or aminoallyl carbonate 297 (Scheme 97). [280] Compared to the palladium-catalyzed allylation reaction, the iridium-or molybdenum-catalyzed allylation occurred at the more substituted end to afford the sterically and electronically preferred alkene-metal complexes, which may explain the preferred formation of the branched products.…”

Iridium‐Catalyzed Asymmetric Allylic Substitutions—Very High Regioselectivity and Air Stability with a Catalyst Derived from Dibenzo[a,e]cyclooctatetraene and a Phosphoramidite

“…Clearly, reversal of C À H activation must have occurred. The source of the requisite HCl must have been residual nPrNH 3 Cl not removed by evaporation. This result indicates that an equilibrium exists between K1 and K2.…”

“…The catalyst system is stable against water and alcohols; however, enantioselectivity in these solvents is lower than in THF. 4) Regioselectivity can be as low as 3:1 (2/3), for example, with substrates 1 b-e. [3] We have now developed a modified catalyst derived from dibenzo[a,e]cyclooctatetraene (dbcot) and L2, which allows substitutions to be run without inert gas for the first time. In addition, regioselectivities with the new catalyst are considerably improved over those with presently used catalysts.…”