JSFiddle - React, Tailwind, and code Playground

HTML

<select name="ramal[]" id="ramal" multiple>
    <option value="all" id="check-all" selected>Todas</option>
    <option class="check-ramal" value="ramal1">$ramal1</option>
    <option class="check-ramal" value="ramal2">$ramal2</option>
    <option class="check-ramal" value="ramal3">$ramal3</option>
    <option class="check-ramal" value="ramal4">$ramal4</option>
</select>

CSS

select,
option {
    padding: 5px;
}

JavaScript

$('#ramal').change(function() {
	var todas = this.querySelector('#check-all');
    var todasAtivo = this.querySelectorAll('option:checked').length == 1 && todas.selected;
	if (!todasAtivo) todas.selected = false;
});