Amphoteric α-Boryl Aldehyde Linchpins in the Synthesis of Heterocycles

Pairing of mutually reactive functional groups in the same molecule affords enabling opportunities in chemical synthesis. Kinetically amphoteric molecules exemplify this scenario and help avoid the pitfalls of protecting-group chemistry by exploiting the innate reactivity of the functional groups. In this perspective, we highlight the recent development of MIDA ( N -methyliminodiacetyl) α-boryl aldehydes as amphoteric building blocks that act as linchpins in the synthesis of heterocycles. This short review includes topics ranging from metal-catalyzed cyclization involving B–C–Pd intermediates to the intramolecular Suzuki–Miyaura cross-coupling that affords six- and seven-membered rings. The use of boryl aldehydes in other transformations, including halogenation and oxidation protocols, is also discussed.