System.config({
    map: {
        'angular2-recaptcha': 'node_modules/angular2-recaptcha'
    },
    packages: {
        app: {
            format: 'register',
            defaultExtension: 'js'
        },
        'angular2-recaptcha': {defaultExtension: 'js', main:'index'}
    }
});

<script src="systemjs.config.js"></script>
 <script>
 System.import('app').catch(function(err){ console.error(err); });
</script>

Uncaught ReferenceError: System is not defined
    at localhost/:29
compiler.es5.js:15996 Uncaught Error: Unexpected module 'ReCaptchaModule' declared by the module 'AppModule'. Please add a @Pipe/@Directive/@Component annotation.
    at syntaxError (compiler.es5.js:1690)
    at compiler.es5.js:15430
    at Array.forEach (<anonymous>)
    at CompileMetadataResolver.webpackJsonp.../../../compiler/@angular/compiler.es5.js.CompileMetadataResolver.getNgModuleMetadata (compiler.es5.js:15412)
    at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler._loadModules (compiler.es5.js:26795)
    at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler._compileModuleAndComponents (compiler.es5.js:26768)
    at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler.compileModuleAsync (compiler.es5.js:26697)
    at PlatformRef_.webpackJsonp.../../../core/@angular/core.es5.js.PlatformRef_._bootstrapModuleWithZone (core.es5.js:4536)
    at PlatformRef_.webpackJsonp.../../../core/@angular/core.es5.js.PlatformRef_.bootstrapModule (core.es5.js:4522)
    at Object.../../../../../src/main.ts (main.ts:11)