Abstract
Organic bases are important class of reagents for synthetic chemistry. Recent developments in optimizing the basicity and in reducing nucleophilicity provide various new synthetic methodologies. This review describes synthetic applications of two excellent organic superbases. One is phosphazene base developed by Schwesinger and the other is proazaphosphatrane base, which was first synthesized by Verkade. The bacisity of the Schwesinger's P 4 base is in the range of organolithium bases and 18 orders of magnitude more basic than conventional DBU. Verkade bases are also strong bases due to the protonation on the bridgehead phosphorus atom with a resultant transannulation to form the corresponding azaphosphatrane structure. Properties, applications, and synthetic benefits of these bases are discussed.
