Hi @Darren Price ,
Welcome to Microsoft Q&A Platform.
This is not supported in Synapse as it is based on Data Warehouse architecture. Only class types - SCHEMA and OBJECT are supported. As per MS documentation, this command applies only to SQL Database. I confirmed the same with Product team internally.
I would recommend you to provide feedback at the feedback forum. All the feedback you share, is closely monitored by the Synapse Product team and implemented in future releases.
Hope this helps! Please let us know for further queries and we will be glad to assist.