1215212-01-3Relevant academic research and scientific papers
On the scope of trimethylaluminium-promoted 1,2-additions of ArZnX reagents to aldehydes
Glynn, Daniel,Shannon, Jonathan,Woodward, Simon
supporting information; experimental part, p. 1053 - 1060 (2010/05/19)
A practical asymmetric 1, 2 addition of functionalised arylzinc hal ides to aromatic and aliphatic aldehydes is described by the use of amino alcohol catalysis in the presence of AlMe3. The process is simple to carry out, uses only commercially available reagents/ligands and provides moderate to good (80-96% ee) enantioselectivities for a wide range of substrates. Either commercial ArZnX reagents or those prepared in situ from low cost aryl bromides can be used. In the latter case electrophilic functional groups are tolerated (CO2Et, CN). The reaction relies on rapid exchange between ArZnX and AlMe3 to generate mixed organometallic species that lead to the formation of a key intermediate that is distinctly different from the classic "anti" transition states of Noyori. NMR monitoring and related experments have been used to probe the validity of the proposed selective transition state.
