KOC(CH3)3, DBU, and DBN are too sterically hindered to attack tetravalent carbon, but are able to remove a small proton, favoring elimination over substitution.

Is DBN a strong or weak nucleophile?

In contrast to what is generally admitted, these results show that DBU and DBN can act as strong nucleophiles.

What are sterically hindered bases?

As the name suggests, a non-nucleophilic base is a sterically hindered organic base that is a poor nucleophile. ... Typical non-nucleophilic bases are bulky, such that protons can attach to the basic center but alkylation and complexation is inhibited.