<div class="btn-group-vertical">
    <button class="btn btn-default">Button</button>
    <button class="btn btn-default">Button</button>
    <div class="btn-group">
      <button class="btn btn-default dropdown-toggle" type="button" data-toggle="dropdown" id="verticalButtonDropdown">Dropdown <i class="fa fa-caret-down"></i></button>
      <ul class="dropdown-menu " role="menu" aria-labelledby="verticalButtonDropdown">
        <li role="presentation"><a href="#" role="menuitem" tabindex="-1">Dropdown Link</a></li>
        <li role="presentation"><a href="#"  role="menuitem" tabindex="-1">Dropdown Link</a></li>
      </ul>
    </div>
    <button class="btn btn-default">Button</button>
    <button class="btn btn-default">Button</button>
  </div>