\documentclass[12pt,border=1pt,crop,multi=false,tikz,class=scrartcl]{standalone}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{chemfig,chemmacros}
\usepackage{lmodern}
\usetikzlibrary{decorations.pathmorphing}

\chemsetup[chemformula]{font-shape=sf,format=\sffamily}
\renewcommand*{\familydefault}{\sfdefault}
\renewcommand*\printatom[1]{\ensuremath{\mathsf{#1}}}
\setatomsep{2em}
\setdoublesep{.6ex}
\setarrowdefault{,1,semithick}
\setbondstyle{thick}
%\setarrowlabelsep{1em}

\makeatletter
\begin{document}
\definesubmol\nobond{-[,0.25,,,draw=none]}

%\schemedebug{true}
\schemestart[-90]
\subscheme{
    \chemfig{R-[:30]@{aa}(=[::60]O)-[::-60]H}
    \arrow{->[\chemfig{@{bb}\chemabove{O}{\scriptstyle\ominus}H}]}
    \chemfig{R-[:30](-[2]O|\mch)(-[:-80,.9]O@{cc}H)-[:-10]H}
    \arrow{->[\chemfig{@{dd}\chemabove{O}{\scriptstyle\ominus}H}]}
    \chemfig{R-[:30](-[2]O|\mch)(-[:-80,.9]O|\mch)-[:-10]H}
    \chemmove[-stealth, shorten >=2pt, shorten <=1pt]{
    	\draw (bb) .. controls +(north west:1mm) and +(north:8mm) .. ($(bb)!.4!(aa)$) .. controls +(south:13mm) and +(south:8mm) .. (aa) ;
        \draw (dd) .. controls +(north west:3mm) and +(north:8mm) .. ($(dd)!.45!(cc)$) .. controls +(south:5mm) and +(east:5mm) .. (cc) ;
    }
}
\arrow{0}[,0.2]
\subscheme[][west]{
	\chemfig{R-[:30](-[@{bb}2]O|@{aa}\mch)(-[:-80,.9]OH)-[@{cc}:-10]H}
    \arrow{0}[,0]\+\arrow{0}[,0]
    \chemfig{R-[:30]@{dd}(=[::60]O)-[::-60]H}
    \arrow
    \chemfig{R-[:30](=[::60]O)-[::-60]O@{ee}H}
    \arrow{0}[,0]\+\arrow{0}[,0]
    \chemfig{R-[:30](-[2,,,2]@{ff}\mch O)(-[:-80,.9]H)-[:-10]H}
    \arrow
    \chemfig{R-[:30](=[::60]O)-[::-60]O\mch}
    \arrow{0}[,0]\+\arrow{0}[,0]
    \chemfig{R-[:30](-[2]OH)(-[:-80,.9]H)-[:-10]H}
    \chemmove[-stealth, shorten >=2pt, shorten <=1pt]{
    	\draw (aa) .. controls +(east:5mm) and +(east:5mm) .. (bb);
        \draw (cc) .. controls +(north east:8mm) and +(north west:5mm) .. (dd);
        \draw (ff) .. controls +(north west:1mm) and +(north:10mm) .. (ee);
    }
}
\arrow{0}[,0.2]
\subscheme[][west]{
	\chemfig{R-[:30](-[@{bb}2]O|@{aa}\mch)(-[:-80,.9]O\mch)-[@{cc}:-10]H}
    \arrow{0}[,0]\+\arrow{0}[,0]
    \chemfig{R-[:30]@{dd}(=[::60]O)-[::-60]H}
    \arrow
    \chemfig{R-[:30](=[::60]O)-[::-60]O\mch}
    \arrow{0}[,0]\+\arrow{0}[,0]
    \chemfig{R-[:30](-[2,,,2]@{ff}\mch O)(-[:-80,.9]H)-[:-10]H}
    \arrow{->[\ch{H2O}][(solvent)]}
    \chemfig{R-[:30](=[::60]O)-[::-60]O\mch}
    \arrow{0}[,0]\+\arrow{0}[,0]
    \chemfig{R-[:30](-[2]OH)(-[:-80,.9]H)-[:-10]H}
    \chemmove[-stealth, shorten >=2pt, shorten <=1pt]{
    	\draw (aa) .. controls +(east:5mm) and +(east:5mm) .. (bb);
        \draw (cc) .. controls +(north east:8mm) and +(north west:5mm) .. (dd);
     }
}
\schemestop
\end{document}