Problem 1: Ozonolysis Product Identification

Given: An alkene undergoes reductive ozonolysis to give acetone ($CH_{3}COCH_{3}$) and formaldehyde (HCHO). What is the alkene?

Solution:

• Step 1: Reverse the ozonolysis — replace =O with =C.
• Acetone fragment: ($CH_{3}$){2}C=O → this C came from –C($CH_{3}$){2}– with C=C
• Formaldehyde fragment: $H_{2}C$=O → this C came from –$CH_{2}$– with C=C
• Step 2: Connect the two fragments via C=C: ($CH_{3}$)_{2}C=$CH_{2}$ = 2-methylpropene

SMILES: CC(C)=C

Verification: CC(C)=C + $O_{3}$ → ozonide --[Zn/$H_{2}O$]--> ($CH_{3}$)_{2}C=O + $H_{2}C$=O ✓