Table 4.

Addition of Methyl Propiolate to α,β-Unsaturated Aldehydes.

^[a]Isolated yield.

^[b]Enantiomeric excess determined by chiral HPLC.

^[c]Reaction performed using 3 equiv alkyne and 3 equiv Me₂Zn.

^[d]Reaction performed using (R,R)-1.

^[e]Reaction performed using ethyl propiolate.