I'd say the two are distinct, and that vanguardism is a thoroughly unanarchistic concept (it did originate with the Bolsheviks after all, iirc). Personally I'm not a huge fan of Syndicalism, I think the vision that anarcho-syndicalists have for post-revolution society reproduces too many of the intolerable aspects of today's status quo that dominate the individual. However they are at least anarchists, and like other social anarchists they seek to achieve their aims in an horizontal, anarchist way - through a popular revolution (however unlikely that is to happen, and however impossible it is to precisely shape a future society through those means).
Vanguardism on the other hand is inherently elitist and heirarchal. It is a pragmatic compromise that arose when Lenin realised how impractical popular revolution is - Russia had a massive popular revolution in 1905 which fizzled out because of state repression, lack of direction and coordination, and finally liberal factions caving into compromises offered by the state that were then reversed in the following years. Lenin argued that is was necessary to have an ideologically unified revolutionary vanguard - a group of close-knit professional revolutionaries to safeguard the revolutionary ideology, disseminate it to the working classes and remove their 'false consciousness', and command them militarily during the revolution. The Marxist Leninist Vanguard is a project directly aimed at bypassing contesting visions of a post-revolutionary society, and any who would oppose Marxist Leninism. Lenin sure was a swell guy wasn't he? Anyway, I'm sure you can see how that's elitist and heirarchal on an organisational and intellectual level.
Vanguardism is primarily a Marxist idea, not a syndicalist one, but that doesn't mean that syndicalists are immune from behaving in vanguardist ways. Syndicalists seem to have a bad habit of professionalising activism and activists, and their particular revolutionary strategy (revolution-by-industrial-unions'-general-strike) involves copious amounts of condescending 'conciousness raising' of the industrial working class - a demographic that is, at least in the developed West, no longer anywhere near as large, relevent or potent as it used to be.