Molecular Complexity and Retrosynthesis

An atom-environment
complexity measure, CA, to assess local
changes in complexity during synthetic transformations
is described. The complexity measure is based on applying Shannon’s
equation to the number and diversity of paths up to two bonds in length
emanating from an atom node. The method requires no explicit accounting
for bond type, stereochemistry, ring membership, symmetry, or molecular
size. CA varies with expectation across
a number of basic reaction examples and may identify the key disconnections
to guide retrosynthesis.