What is "triazabicyclodecene"

Triazabicyclodecene (1,5,7-Triazabicyclo[4.4.0]dec-5-ene or TBD) is a commercially available bicyclic strong guanidine base (pK = 25.98 in CHCN and pK = 21.00 in THF). TBD is an organic soluble base which has been used effectively for a variety of base-mediated organic transformations such as:

• Michael reactions,
• Henry ( nitroaldol reactions),
• Wittig reactions,
• Horner–Wadsworth–Emmons reactions,
• transesterification reactions,
• etherifications,
• ring-opening polymerizations (Scheme 1),
• tautomerizations and epimerizations
• P–C and P–N bond formations,
• Knoevenagel condensations,
• deprotonation reactions of phenols, carboxylic acids and C-acids (Scheme 2),
• aminolysis of esters.

It is also known in deprotonated form (at the 7-position), often as a ligand, for instance in Ditungsten tetra(hpp)