diff --git a/pyproject.toml b/pyproject.toml
index 56d7d63..c83a0e5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,10 +2,7 @@
 
 requires = ["setuptools",
             "setuptools_scm",
-            "wheel",
-            "extension-helpers",
-            "oldest-supported-numpy",
-            "cython"]
+]
 
 build-backend = 'setuptools.build_meta'
 
diff --git a/setup.py b/setup.py
index e7f0074..7d32a44 100755
--- a/setup.py
+++ b/setup.py
@@ -9,8 +9,6 @@
 
 from setuptools import setup
 
-from extension_helpers import get_extensions
-
 
 # First provide helpful messages if contributors try and run legacy commands
 # for tests or docs.
@@ -65,5 +63,4 @@
     print(DOCS_HELP)
     sys.exit(1)
 
-setup(use_scm_version={'write_to': os.path.join('specreduce', 'version.py')},
-      ext_modules=get_extensions())
+setup(use_scm_version={'write_to': os.path.join('specreduce', 'version.py')})