Catalytic aldol reactions are among the most useful synthetic methods for highly stereocontrolled asymmetric synthesis. In this account we discuss the recent development of a novel synthetic technique which uses tandem enzyme catalysis for the bi-directional chain elongation of simple dialdehydes and related multi-step procedures. The scope and the limitations of multiple one-pot enzymatic C-C bond formations is evaluated for the synthesis of unique and structurally complex carbohydrate-related compounds that maybe regarded as metabolically stable mimetics of oligosaccharides and that are thus of interest because of their potential bioactivity.