Write the structural formulae and names of the four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde served as electrophile and which as nucleophile?
(i) Propanal acts as both nucleophile and electrophile.
(ii) Butanal serves as both nucleophile and electrophile.
(iii) Propanal serves as electrophile and butanal as nucleophile.
(iv) Butanal serves as electrophile and propanal as nucleophile.