var res = exitDictionary
.Select(p => p.Value).Cast<Dictionary<string, object>>()
.SelectMany(d => d)
.Where(p => p.Key == "fieldname1")
.Select(p => p.Value).Cast<List<Dictionary<string,string>>>()
.SelectMany(l => l)
.SelectMany(d=> d)
.Where(p => p.Key == "valueTitle")
.Select(p => p.Value)
.ToList();
This also works, and easy to understand.