Try pandoc!
Convert
from
CommonMark
Creole
DocBook
DokuWiki
FB2
Haddock markup
HTML
JATS
Jupyter Notebook (ipynb)
LaTeX
Man
Markdown (pandoc)
Markdown (GitHub-flavored)
Markdown (PHP Markdown Extra)
Markdown (strict)
MediaWiki
MultiMarkdown
Muse
Native (Pandoc AST)
OPML
Org Mode
reStructuredText
Txt2Tags
Textile
TikiWiki
TWiki
Vimwiki
to
S5
AsciiDoc (original)
AsciiDoc (asciidoctor-flavored)
LaTeX Beamer
CommonMark
ConTeXt
DocBook v4
DocBook v5
DokuWiki
DZSlides
Haddock markup
HTML 4
HTML 5
ICML
JATS
Jira
JSON
Jupyter Notebook (ipynb)
LaTeX
Man
Ms
Markdown (pandoc)
Markdown (GitHub-flavored)
Markdown (PHP Markdown Extra)
Markdown (strict)
MediaWiki
MultiMarkdown
Muse
Native (Pandoc AST)
OpenDocument
OPML
Org Mode
Plain text
reveal.js
reStructuredText
RTF
Slideous
Slidy
TEI
Texinfo
Textile
ZimWiki