Using TRY...CATCH in Transact-SQL - sql-server

Question

I have the written the T-SQL code below. I want to put it in a SQL Server TRY...CATCH block. However, because I must execute some statements before proceeding with another statement, I am using the GO keyword and this makes the code crash with out executing the code in the CATCH block. It just crashes as if there was no CATCH block. If I remove the GOs in the code and the code crashes, the execution jumps to the CATCH block which is the desired behavior.
Any ideas on what I can do?
BEGIN TRY
RESTORE FILELISTONLY
FROM DISK = 'D:\Folder1\Database1.bak'
GO
ALTER DATABASE BusinessData
SET SINGLE_USER WITH
ROLLBACK IMMEDIATE
ALTER DATABASE BusinessData
SET RECOVERY Simple
RESTORE DATABASE BusinessData
FROM DISK = 'D:\Folder1\Database1.bak'
WITH MOVE 'BusinessData' TO 'C:\MyDATA
\BusinessData.mdf',
MOVE 'BusinessData_log' TO 'C:\MyDATA
\BusinessData_log.ldf'
ALTER DATABASE BusinessData SET MULTI_USER
GO
IF NOT EXISTS (SELECT * FROM sys.server_principals WHERE name = N'SERVER1\user1')
CREATE LOGIN [SERVER1\user1] FROM WINDOWS WITH DEFAULT_DATABASE=[master], DEFAULT_LANGUAGE=
[us_english]
GO
USE [ProjectServer_Authentication]
GO
IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = N'SERVER1\user1')
CREATE USER [SERVER1\user1] FOR LOGIN [SERVER1\user1] WITH DEFAULT_SCHEMA=[dbo]
GO
EXEC sp_addrolemember 'db_owner',N'SERVER1\user1'
GO
USE [BusinessData]
IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = N'SERVER1\user1')
CREATE USER [SERVER1\user1] FOR LOGIN [SERVER1\user1] WITH DEFAULT_SCHEMA=[dbo]
GO
EXEC sp_addrolemember 'db_owner',N'SERVER1\user1'
GO
END TRY
BEGIN CATCH
USE msdb
GO
EXEC sp_send_dbmail #profile_name='My Mail Profile',
#recipients='myemailaccount#mydomain.org',
#subject='Refresh Error',
#body='Email body'
END CATCH

Answer 1

I think GO is the Problem as
GO is not a Transact-SQL statement;
it is a command recognized by the sqlcmd and osql utilities and SQL Server Management Studio Code editor.
SQL Server utilities interpret GO as a signal that they should send the current batch of Transact-SQL statements to an instance of SQL Server. The current batch of statements is composed of all statements entered since the last GO, or since the start of the ad hoc session or script if this is the first GO.
With every GO you start a new Statement, wich means your begin Try and your End Try are in 2 different Statements and therefore not working