The Diels–Alder reaction that involves a nitrogen atom in the diene or dienophile is termed the aza-Diels–Alder reaction.

Solar radiation is the principal source of energy available to Earth and has unmatched potential for the synthesis of organic material from primordial molecular building blocks. As well as providing the energy for photochemical synthesis of (proto)biomolecules of interest in origins of life-related research, light has also been found to often provide remarkable selectivity in these processes, for molecules that function in extant biology and against those that do not. As such, light is heavily implicated as an environmental input on the nascent Earth that was important for the emergence of complex yet selective chemical systems underpinning life. Reactivity and selectivity in photochemical prebiotic synthesis are discussed, as are their implications for origins of life scenarios and their plausibility, and the future directions of this research.

The complexity of the simplest conceivable cell suggests that the chemistry of prebiotic mixtures needs to be explored to understand the intricate network of prebiotic reactions that led to the emergence of life.