Carbon-Based Leaving Group in Substitution Reactions: Functionalization of sp3-Hybridized Quaternary and Tertiary Benzylic Carbon Centers

Lewis acid promoted substitution reactions employing Meldrum's acid and 5-methyl Meldrum's acid as carbon-based leaving groups are described which transform unstrained quaternary and tertiary benzylic C-sp3-C-sp3 bonds into C-sp3-X bonds (X = C, H, N). Importantly, this reaction has a broad scope in terms of both suitable substrates and nucleophiles with good to excellent yields obtained (typically >90%).