pattern.cs

var symbols = UnitBase.AllUnitsStatic.Select(x => x.Symbol).ToArray();
var symbolsPattern = string.Join("|", new[] { "1" }.Concat(symbols));
var pattern = string.Format(@"(?<Unit>
                                    (?<Symbol>({0}))
                                    (
                                        (?:\^)
                                        (?<Power>[+-]?\d+)
                                    )?
                                   |
                                   (?<Op>[⋅\*\/])
                              )",  symbolsPattern);
var matches = Regex.Matches(s, pattern, RegexOptions.IgnorePatternWhitespace);