Asymmetricconjugate alkylation reaction of racemic 5-substituted cyclohexenones with dialkylzinc reagents was catalyzed by 2–5 mol % of dipeptidic amidophosphane-Cu(MeCN)4BF4 in toluene at 0 °C for 20 min to recover enantioenriched starting 5-substituted cyclohexenones with 88–98% ee in 28–41% yield along with trans major 3-alkylated 5-substituted cyclohexanones with 81–90% ee in 53–60% yield. Complete
Mass spectrometry is the best physical method for the configurational assignment of E- and Z-3,5-dialkylcyclohexylidene acetic acid esters 1 and E- and Z-3-alkyl-2-alkenoates 2. The homoallylic cleavage resulting in the loss of the C-3 and C-5 alkyl groups from 1 and of the two δ-alkyls from 2 is a stereospecific process: the loss of the group which is adjacent to the carbonyl is significantly preferred