Modification of metabolic pathways includes genetically engineering at least one enzyme involved in elongating 2-ketoacids during leucine biosynthesis, and preferably at least isopropylmalate dehydrogenase or synthase (LeuB or LeuA in E. coli), to include at least such non-native enzyme, enzyme complex, or combination thereof to convert 2-ketobutyrate or 2-ketoisovalerate to a C7-C11 2-ketoacid, wherein the production of such is at a higher efficiency than if a purely native pathway is followed. The C7-C11 2-ketoacid may then be converted, via a native or genetically engineered thiamin dependent decarboxylase, to form a C6-C10 aldehyde having one less carbon than the C7-C11 2-ketoacid being converted. In some embodiments the C6-C10 aldehyde may then be converted via additional native or genetically engineered enzymes to form other C6-C10 products, including alcohols, carboxylic acids, and alkanes. This genetic engineering offers the opportunity for commercial scale of in vivo biosynthetic processes that may be more cost-efficient than non-biobased approaches to produce the same products.