1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) as a Lewis Base

Introduction

1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD, 1) was first synthesized by McKay and Kreling in the laboratories of Monsanto Canada Limited in 1957.[1] This bicyclic guanidine possesses a remarkably high Brønsted basicity (pK_a = 28 in MeCN)[2] and has found broad applications as an organic superbase.[3] Moreover, the nucleophilic properties of guanidines have also been studied.[4] Mayr and co-workers quantified the nucleophilicities for a series of guanidines,[5] and TBD was by far the most powerful nucleophile among the investigated structures. In fact, TBD was found to be an even stronger nucleophile than the well-known Lewis base 4-dimethylaminopyridine (DMAP). In order to highlight the synthetic utility and usefulness of TBD as a Lewis base, a short overview of recent applications is presented.

Figure 1 Commercially available bicyclic guanidine base 1,5,7-tri­a­zabicyclo[4.4.0]dec-5-ene (TBD, 1)

• References

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