First create a menu Products .

Settings>>Technical>>User Interface>>Menu Items

create this hierarchy :

• Menu : Products , Parent Menu : none , Action : none
• Menu : Products Item , Parent Menu : Products , Action : None
• Menu :List of Products , Parent Menu : Products Item , Action : ir.actions.report.xml and choose Products

in group Portal ( or create a new group) tab Menus add these menus .and delete others menus.

in tab Access Rights product.template , product.product ,.. .by warning message Access Rights.

or you can create a new module to define this group.