Copper-Catalyzed Highly Enantioselective Synthesis of Cyclic Allylic and Homoallylic Alcohols with Dialkylzinc Reagents

Abstract

The copper-phosphoramidite catalyzed addition of dialkylzinc reagents to racemic or meso allylic epoxides can be synthetically exploited in different ways, depending on the substrates and reaction conditions used.

asymmetric catalysis - organozinc reagents - copper - kinetic resolution - desymmetrization

References

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<A NAME="RZ10404SS-2B">2b</A> Chiral ligand 1 was recently used in the iridium-catalyzed allylic etherification and amination of achiral allylic esters: Ohmura T. Hartwig JF. J. Am. Chem. Soc.  2002,  124:  15164 

<A NAME="RZ10404SS-2C">2c</A> Also see: Lopez F. Ohmura T. Hartwig JF. J. Am. Chem. Soc.  2003,  125:  3426 

( S,R,R )-Diastereoisomeric phosphoramidite, derived from (S)-BINOL and (R)-bis-phenylethylamine developed by Feringa et al. is to date one of the most effective chiral ligand for several copper-catalyzed enantioselective conjugate additions. For some recent examples, see:

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<A NAME="RZ10404SS-12">12</A>

In this case, the use of lower amounts of the chiral catalyst (<1.0 mol%) gave a very sluggish reaction.