<div class="container">
<div class="row">
<div class="col-md-6">
left block
</div>
<div class="col-md-6">
<div class="row">
<div class="col-md-6">
<div class="right-block">
right block
</div>
</div>
<div class="col-md-6">
<div class="right-block">
right block
</div>
</div>
<div class="col-md-6">
<div class="right-block">
right block
</div>
</div>
<div class="col-md-6">
<div class="right-block">
right block
</div>
</div>
</div>
</div>
</div>
</div>