2-Phospha- and 2,3-Oxaphosphabicyclo[2.2.2]octenes - Synthesis and Fragmentation to Low-coordinated Species

The 2-phosphabicyclo[2.2.2]octene and 2,3-oxaphosphabicyclo[2.2.2]octene systems undergo fragmentation in inert solvents on heating, or by UV-irradiation at room or low temperature. The fragmentation is of significance because it leads to the extrusion of low-coordinated species Y-P(X)O (Y = RO, R2N, Aryl; X = O, S, CH2), which are very effective phosphorylating agents. This review covers different aspects of the 2-phosphabicyclo[2.2.2]octene and 2,3-oxaphosphabicyclo[2.2.2]octene derivatives. The first part is focused on their synthesis and structure. The reactivity of 2,3-oxaphosphabicyclooctenes involving rearrangement and fragmentation with release of the bridging P-O unit including mechanistic studies is described in the next part. The last part of the review is dedicated to the practical aspects of the utilization these compounds as phosphorylating agents.