Fig. 3: Isotopic labeling experiments.
From: Chemodivergent transformations of amides using gem-diborylalkanes as pro-nucleophiles

a 18O-labeling experiment of primary amide P1. b 18O-labeling experiment of secondary amide S1. c 18O-labeling experiment of tertiary amide T1. d Deuterium-labeling experiment of tertiary amide T1.