documentclass{report}
usepackage[T2A]{fontenc}
usepackage[cp1251]{inputenc}
usepackage[english,russian]{babel}
usepackage{chemfig}
usepackage{tikz}
usetikzlibrary{decorations,arrows,shapes,snakes,automata,positioning}


makeatletter
definearrow1{s>}{%
ifx@empty#1@empty
expandafterdrawexpandafter[CF@arrow@current@style,CF](
CF@arrow@start@node)(
CF@arrow@end@node);%
else
defcurvedarrow@style{shorten <=CF@arrow@offset,shorten >=CF@arrow@offset,}%
CF@expadd@tocscurvedarrow@styleCF@arrow@current@style
expandafterdrawexpandafter[curvedarrow@style,CF](
CF@arrow@start@name)..controls#1..(CF@arrow@end@name);
fi
}
makeatother

begin{document}
setchemfig{scheme debug=false}

pgfdeclaredecoration{ddbond}{initial}{%
state{initial}[width=2pt]{%
pgfpathlineto{pgfpoint{2pt}{0pt}}%
pgfpathmoveto{pgfpoint{1.5pt}{2pt}}%
pgfpathlineto{pgfpoint{2pt}{2pt}}%
pgfpathmoveto{pgfpoint{2pt}{0pt}}%
 }%
state{final}{%
pgfpathlineto{pgfpointdecoratedpathlast}%
 }%
 }%
tikzset{lddbond/.style={decorate,decoration=ddbond}}%
tikzset{rddbond/.style={decorate,decoration={ddbond,mirror}}}

scalebox{.7}{
schemestart
chemfig{H_3C-[:-30]CH_2-[:30]C(=[:90]O)-[:-30]OH}
arrow(str1.south west--str21.north east[yshift=2mm])[-150,1.71]
chemfig{H_3C-[:-30]CH_2-[:30]chembelow{C}{*}=[:90]O}
arrow(@str1.south--str22.north)[-135]
chemfig{H_3C-[:-30]chemabove{C}{*}H-[:30]C(=[:90]O)-[:-30]OH}
arrow(str22.east--str23.west)[,0.5]
chemfig{H_3C-[:-30]chembelow{C}{**}H}
arrow(@str1.south east--str24.north west[yshift=0mm])[-30,1.71]
chemfig{H_3C-[:-30]CH_2-[:30]C(-[:75,,,,rddbond]O)(-[,0.5,,,draw=none]chemabove{hphantom{H}}{*})-[:-45,,,,lddbond]O}
arrow(@str21.south west--str31.north east[yshift=-4mm])[-135,1.41]
chemfig{H_3C-[:-45]chembelow{C}{*}H_2}
arrow(@str21.south west--str32.north)[-90]
chemfig{H_3C-[:-45]chemabove{C}{*}H-[:30]chembelow{C}{*}=[:90]O}
arrow(@str22.south--@str32.north east)[-135,1.41]
arrow(@str22.south--str33.north)[-140, 1.45]
chemfig{H_2C=[:-30]CH-[:30]C(=[:90]O)-[:-30]OH}
arrow(@str22.south--str34.north)[-40,1.45]
chemfig{H_3C-[:-30]chembelow{C}{**}-[:30]C(=[:90]O)-[:-30]OH}
arrow(@str22.south--str35.north west[yshift=2mm])[-22.5,3]
chemfig{H_3C-[:-30]chembelow{C}{*}H-[:30]C(-[:75,,,,rddbond]O)(-[,0.5,,,draw=none]chemabove{hphantom{H}}{*})-[:-45,,,,lddbond]O}
arrow(@str24.south--@str35.north)
arrow(@str24.south--str36.north[yshift=-4mm])[-45, 1.41]
chemfig{H_3C-[:-30]chembelow{C}{*}H_2}
arrow(@str31.south west--str41.north[yshift=-6mm])[-135, 1.41]
chemfig{H_3C-[:-30]CH_3}
arrow(@str32.south--str42.north east[yshift=-2mm])[-135, 1.41]
chemfig{H_3C-[:-30]chembelow{C}{**}H}
arrow(@str42.north--@str31.south)
arrow(@str32.south--str43.north)[-90]
chemfig{H_3C-[:-45]chemabove{C}{*}=[:30]C=[:90]O}
arrow(@str33.south--str44.north)[-120,1.2]
chemfig{H_2C=[:-30]CH-[:30]chembelow{C}{*}=[:90]O}
arrow(@str32.south--@str44.north west)
arrow(@str33.south--str45.north[yshift=-3mm])[-30,1.6]
chemfig{Hchemabove{C}{*}=[:-30]CH-[:30]C(=[:90]O)-[:-30]OH}
arrow(@str35.south--str46.north[yshift=3mm])[-135,1.41]
chemfig{H_3C-[:-30]chembelow{C}{**}-[:30]C(-[:75,,,,rddbond]O)(-[,0.5,,,draw=none]chemabove{hphantom{H}}{*})-[:-45,,,,lddbond]O}
arrow(@str34.south--@str46.north)
arrow(@str35.south--str47.north)[-45,1.41]
chemfig{H_3C-[:-30]chembelow{C}{**}H}
arrow(@str43.south--str51.north east[yshift=-2mm])[-135, 1.41]
chemfig{H_3C-[:-30]chembelow{C}{***}}
arrow(@str51.north--@str42.south)
arrow(@str44.south--str52.north[yshift=-2mm])[-90]
chemfig{H_2C=[:-45]chembelow{C}{*}H}
%arrow(@str33.south--@str52.north east){s>[+(-45:1cm)and+(45:1cm)]}
arrow(@str45.south--str53.north[yshift=3mm])[-90]
chemfig{Hchemabove{C}{*}=[:-30]CH-[:30]chembelow{C}{*}=[:90]O}
arrow(@str44.south--@str53.north west[yshift=2mm])
arrow(@str46.south--str54.north[yshift=-2mm])[-90]
chemfig{H_3C-[:-30]chembelow{C}{***}}
arrow(@str52.south--str62.north[yshift=-2mm])[-90]
chemfig{H_2C=[:-45]CH_2}
arrow(@str62.west--str61.east)[180]
chemfig{H_3C-[:-45]chembelow{C}{*}H_2}
arrow(@str53.south--str63.north)[-90]
chemfig{HC~[:-45]CH}
arrow(@str63.north west--@str52.south east)
schemestop}

end{document}

arrow(@str33.south--@str52.north east){s>[+(-45:1cm)and+(45:1cm)]}