Carbon oxides, such as carbon monoxide (CO) and carbon dioxide (CO2), offer an intriguing potential to build carbon-carbon bonds directly with high atom efficiency. The ideology is inspired by nature, where enzymes are known to use CO2 and H2O in the production of complex sugars during photosynthesis. Some have suggested that even under prebiotic conditions that CO may be one of nature's building blocks for sugars. These 'C1 building blocks' are commonly discussed in terms of their toxicity or negative impact as greenhouse gases; their industrial value can be underappreciated.