(A) Ligation of AOB to phage-displayed aldehydes is accelerated by aniline, but preincubation of phage with aniline in the absence of AOB leads to rapid loss of aldehyde and loss of reactivity toward AOB. (B) In anilinium acetate, pH 4.7, the aldehyde disappears with t1/2 ∼40 min; however, aldehydes alone are stable at the same pH in sodium acetate buffer.

Scope of aniline partners 2b–2j.