The goal is to have an environment that takes a citation key and displays it in a section header, among other things. I've simplified the environment considerably for the sake of an MWE. The code is:
\documentclass[10pt]{article}
\usepackage[globalcitecopy,subsectionbib]{bibunits}
\usepackage[round]{natbib}
\usepackage[nottoc,numbib]{tocbibind}
\begin{filecontents*}{mwecitations.bib}
@book{goossens93,
author = "Frank Mittelbach and Michel Goossens and Johannes Braams and David Carlisle and Chris Rowley",
title = "The {LaTeX} Companion",
year = "1993",
publisher = "Addison-Wesley",
address = "Reading, Massachusetts"
}
@article{fujita2010economic,
title={Economic effects of the unemployment insurance benefit},
author={Fujita, Shigeru},
journal={FRB Phil. Business Review},
volume={4},
year={2010}
}
@article{rothstein2011unemployment,
title={Unemployment insurance and job search in the {Great Recession}},
author={Rothstein, Jesse},
journal={NBER},
volume={w17534},
year={2011}
}
\end{filecontents*}
\newenvironment{thediscussion}[1]{\section*{\cite*{#1}}}{\putbib \pagebreak}
\defaultbibliography{mwecitations}
\defaultbibliographystyle{plainnat}
\bibliographystyle{plainnat}
\begin{document}
\bibliographyunit[\section]
\tableofcontents
\begin{thediscussion}[goossens93]
Discussion goes here.
\end{thediscussion}
\begin{thediscussion}[rothstein2011unemployment]
More discussion here.
Additional citations are \cite*{rothstein2011unemployment} and \cite*{fujita2010economic}.
\end{thediscussion}
\section{Appendix}
\renewcommand{\bibname}{Global bibliography}
\bibliography{mwecitations}
\end{document}
The output looks very strange:
It seems like the sections aren't being recognized, or I've entered the environment argument incorrectly. What am I doing wrong?

\section*with\sectionin the environment definition, the headers do appear in the table of contents, but with section numbers, which I was trying to avoid in the first place. – Michael A Sep 05 '17 at 13:40