90113-08-9Relevant academic research and scientific papers
Chelation vs. non-chelation control in addition reactions of ethylmetallyc reagents to acrolein dimer
Singh, Shankar M.,Oehlschlager, Allan C.
, p. 209 - 213 (2007/10/02)
Reactions of 3,4-dihydro-2H-pyran-2-carboxaldehyde (acrolein dimer) with ethylmetallics based on lithium, titanium, and copper were examined for stereoselectivity.High selectivity (92:8) was found for non-chelation controlled addition yielding the erythro product when ethyllithium was employed in the presence of BF3*OEt2.High selectivity (89:11) for products of chelation controlled addition (threo) was observed for ethylcopper reagents in the presence of magnesium salts.Titanium reagents yielded mixtures rich in products of either chelation or non-cheletion controlled addition depending on the titanium substituents.In no cases were stereoselectivities obtained with titanium reagents better than those obtained by use of the aforementioned lithium and copper reagents.
