Hydrofunctionalisation of an Aromatic Triphosphabenzene

The aromatic heterocycle 2,4,6‐tri‐tert‐butyl‐1,3,5‐triphosphabenzene reacts with a series of silanes, germanes and stannanes, with weaker E−H bonds reacting in an increasingly facile manner. All react by 1,4‐addition to give bicyclic products with diastereomeric ratios varying with the substrate. Density functional theory (DFT) calculations show that activation of the E−H bond occurs across the 1,4‐C/P axis of the triphosphabenzene, with the small energetic differences with respect to the stereochemistry of the addition offering insight into the experimentally observed diastereomeric ratios.