Regioselective and Chemoselective Reduction of 𝜶,𝜷-Unsaturated Carbonyl Compounds by NaBH₄/Ba(OAc)₂ as a Reducing System

Table 3

Competitive reduction of cinnamaldehyde with enones by NaBH₄/Ba(OAc)₂ as a reducing system at room temperature in CH₃CN.

Entry	Enone	Molar ratio^a	Time (min)	1,2-reduction of cinnamaldehyde/enone (%)^b
1	Benzylideneacetone	1 : 1 : 0.5 : 0.2	5	100 : 0
2	Chalcone	1 : 1 : 0.5 : 0.2	5	100 : 0
3	β-ionone	1 : 1 : 0.5 : 0.2	5	100 : 0
4	2-cyclohexenone	1 : 1 : 0.5 : 0.2	5	100 : 0
5	3-methyl-2-cyclopentenone	1 : 1 : 0.5 : 0.2	5	100 : 0

 ^aMolar ratio as substrate: cinnamaldehyde : enone : NaBH₄ : Ba(OAc)₂; ^bcompletion of the reactions was monitored by TLC (eluent; n-hexane/EtOAc: 9/1).