(R) 4-deutero pentanal.
How many aldol products are formed?

For (R)-4-deuteropentanal (CH₃CHDCH₂CH₂CHO), when treated with dilute KOH (aldol reaction conditions), two aldol products are formed.

Explanation

• 4-deuteropentanal is chiral (D at C-4), and it can undergo self-aldol reaction.
• Aldol addition can occur via enolization at either αα-position of the aldehyde (C-2 and C-4), but since C-4 is chiral and contains D, and the molecule is not symmetric:
  • The enolate can be formed with respect to H or D at C-4, resulting in two diastereomeric aldol products due to different stereochemistry at C-4.
• Thus, two different aldol products will arise from the reaction of (R)-4-deuteropentanal with itself.

Final answer:
Two aldol products are formed from (R) 4-deuteropentanal when reacted with dilute KOH (self-aldol condensation).