Example utilize csc.exe from cake

csc.cake

DirectoryPath   projectPath     = MakeAbsolute(Directory("./cscTest"));
DirectoryPath   outputPath      = projectPath.Combine("bin/Debug");
FilePath        asssemblyPath   = outputPath.CombineWithFilePath("Test.dll"),
                symbolsPath     = outputPath.CombineWithFilePath("Test.pdb");

FilePath[]      references      = new FilePath[0]; // add any assembly dependencies

Task("Clean")
    .Does(() => {
        CleanDirectory(outputPath);
});


Task("Build")
    .IsDependentOn("Clean")
    .Does(() => {
        var arguments = new ProcessArgumentBuilder()
                                .Append("/debug")
                                .AppendSwitch("/target", ":", "library") // exe, winexe...
                                .AppendSwitchQuoted("/out",":", asssemblyPath.FullPath)
                                .AppendSwitchQuoted("/pdb",":", symbolsPath.FullPath)
                                .Append("/recurse:*.cs");

        Array.ForEach(
            references,
            refeence => arguments.AppendSwitchQuoted("/reference", ":", refeence.FullPath)
            );

        var result = StartProcess(
            "csc.exe", // needs to be full path if not in path
            new ProcessSettings {
                WorkingDirectory = projectPath,
                Arguments = arguments
            }
            );

        if (result != 0)
        {
            throw new Exception(string.Format("csc.exe exited with {0}", result));
        }
});


RunTarget("Build");