It seems you need to add " System.Runtime.Serialization " to " frameworkAssemblies ".
See an example project.json file:
"net45": { "frameworkAssemblies": { "System.Runtime.Serialization": "4.0.0.0" }, "dependencies": { "System.Reflection": "4.0.10-beta-22416", "System.Reflection.Extensions": "4.0.0-beta-22526", "System.Reflection.Primitives": "4.0.0-beta-22526", "System.Reflection.TypeExtensions": "4.0.0-beta-22526", "System.Collections": "4.0.10-beta-22526", "System.Collections.Specialized": "4.0.0-beta-22526", "System.Linq": "4.0.0-beta-22526", "System.Linq.Expressions": "4.0.0-beta-22526", "System.Linq.Queryable": "4.0.0-beta-22526", "System.Runtime": "4.0.20-beta-22526", "System.Runtime.Serialization.Primitives": "4.0.0-beta-22526", "System.Runtime.Serialization.Xml": "4.0.10-beta-22526", "System.Runtime.Serialization.Json": "4.0.0.0-beta-22526" } }
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