Identify the reagents 5: answers

Back in August I posted a scheme for the synthesis of a late-stage intermediate towards PF-06826647, a compound identified by Pfizer as a potent and selective tyrosine kinase 2 (TYK-2) inhibitor. I asked if you could identify reagents or intermediates A, B and D. Below are the answers! You can read more here in the full reference: B. Gerstenberger et al, J. Med. Chem. 2020, 63, 13651-13577