How to illustrate an isomerisation mechanism with chemfig

Question

I'd like to produce a scheme of the isomerisation mechanism of hop alpha-acids during wort boiling in beer as featured in Verzele, 1986. (Don't worry, I'll post the link for the article). I'd like to reproduce clearly the mechanism of Figure 5 (p. 34 or the 3rd page if you prefer). It looks shitty when I wanted to include the figure, plus it seems weird since the rest of my figures have been produce with \chemfig.

The only challenge that I have is to ad the arrows to structure V of the figure and put \ominus on the side instead floating next to an atom of oxygen.

Here's what I've done so far for structure V:

\chemfig{*6((-HO)-(([:240]<:HO)(<[:300]-[:270]=[:330](-[:30])-[:270]))-(-[,,,,,lddbond]O)-[,,,,,rddbond](-[:30,,,,,lddbond]([:90,,,,,lddbond]-O)-[:330]R)-[,,,,,rddbond](-[,,,,,rddbond]O^{\ominus})-(-[:150]-[:210]=[:150](-[:90])-[:210])=)}

Here's the link of the article: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1986.tb04372.x/pdf

Answer 1

Taken the code from the other answer (and not verifying if the formulae match the picture) I came up with the following. For the numbering I use the chemnum package (but you should use more meaningful names than me, I chose one, two, three…). For formal charges, the cis/trans nomenclature and the molecules on the arrows I use the chemmacros/chemformula packages. The package showframe is used to visualize page dimensions.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{chemfig}

\usepackage{chemnum,chemmacros}

\usetikzlibrary{decorations}
\pgfdeclaredecoration{ddbond}{initial}{
  \state{initial}[width=4pt]{
    \pgfpathlineto{\pgfpoint{4pt}{0pt}}
    \pgfpathmoveto{\pgfpoint{2pt}{2pt}}
    \pgfpathlineto{\pgfpoint{4pt}{2pt}}
    \pgfpathmoveto{\pgfpoint{4pt}{0pt}}
  }
  \state{final}{
    \pgfpathlineto{\pgfpointdecoratedpathlast}
  }
}
\tikzset{lddbond/.style={decorate, decoration=ddbond}}
\tikzset{rddbond/.style={decorate, decoration={ddbond, mirror}}}

\usepackage{showframe}

\begin{document}

\begin{center}
  \scriptsize
  \setchemfig{
    atom sep = 1.2em,
    cram width = .3em,
    bond offset = .1em
  }
  \schemestart
    % 1
    \chemname{\chemfig{*6((-HO)-(([:240]-(-[:270]=[:210](-[:150])-[:270]))(-[:300]-[:270]=[:330](-[:30])-[:270]))-(=O)-(-[:30]([:90]=O)-[:330]-[:30](-[:90])-[:-30])=(-OH)-(-[:150]-[:210]=[:150](-[:90])-[:210])=)}}{\cmpd{one}}
    \arrow{0}[,.5]
    % 2
    \chemname{\chemfig{*6((-HO)-(([:240]<:HO)(<[:300]-[:270]=[:330](-[:30])-[:270]))-(=O)-(-[:30]([:90]=O)-[:330]-[:30](-[:90])-[:-30])=(-OH)-(-[:150]-[:210]=[:150](-[:90])-[:210])=)}}{\cmpd{two}:
    Humulone}
    \arrow{->[\ch{OH-}][$\Delta$]}[,1.5]
    % 3
    \chemname{\chemfig{*6((-[:-150]O-[:180]H)-(([:240]<:HO)(<[:300]-[:270]=[:330](-[:30])-[:270]))-(-[,,,,,lddbond]O)-[,,,,,rddbond](-[:30,,,,,lddbond]([:90,,,,,lddbond]-O)-[:330]-[:30](-[:90])-[:-30])-[,,,,,rddbond](-[,,,,,rddbond]O|^{\fminus})-(-[:150]-[:210]=[:150](-[:90])-[:210])=)}}{\cmpd{three}}
    \arrow{->[*0\ch{H+}]}[-90]
    % 4
    \chemname[3.5ex]{\chemleft[
      \chemfig{*6((=O)-(([:240]<:HO)(<[:300]-[:270]=[:330](-[:30])-[:270]))-(-[,,,,,lddbond]O)-[,,,,,rddbond](-[:30,,,,,lddbond]([:90,,,,,lddbond]-O)-[:330]-[:30](-[:90])-[:-30])-[,,,,,rddbond](-[,,,,,rddbond]O^{\fminus})-(-[:150]-[:210]=[:150](-[:90])-[:210])-)}
    \chemright]}{\cmpd{four}: ketonized anion intermediate}
    \arrow[-180]
    % 5
    \chemname{\chemfig{*5((<:(-[::60](=[::60]O)-[::-60]-[::60]=[::-60](-[::-60])-[::60]))(<HO)-(-OH)=(-(=[:60]O)-[:-60]-(-[:60])-[:-60])-(=O)-(<:[::-54]-[::+60]=[::-60](-[::-60])-[::+60])-)}}{\cmpd{five}:
    \trans-isohumulone}
    \arrow{0}[-180,.5]
    \chemname{\chemfig{*5((<(-[::60](=[::60]O)-[::-60]-[::60]=[::-60](-[::-60])-[::60]))(<:HO)-(-OH)=(-(=[:60]O)-[:-60]-(-[:60])-[:-60])-(=O)-(<:[::-54]-[::+60]=[::-60](-[::-60])-[::+60])-)}}{\cmpd{six}:
    \cis-isohumulone}
  \schemestop
\end{center}

\end{document}