Post-modification of the isoprenoid ring in pyripyropenes critically modulates their structural diversity and bioactivity. Here, we report the engineered biosynthesis of novel pyripyropene derivatives via reconstruction of the pyripyropene A gene cluster and its heterologous expression in Aspergillus nidulans. Five previously unreported compounds—1-keto-pyripyropene E (1), 13-hydroxy-1-keto-pyripyropene E (2), deacetyl-pyripyropene G (3), 11-deoxo-deacetyl-pyripyropene A (4), and 1-keto-11-deoxo-deacetyl-pyripyropene A (5)—were isolated from the engineered strain. Their structures were unequivocally characterised by MS and NMR spectroscopy, with compounds 1, 2, and 5 representing the first examples of 1-ketone pyripyropenes. Significantly, these 1-ketone derivatives exhibited significantly enhanced insecticidal activity compared to their 1-hydroxy analogues, demonstrating their potential as next-generation insecticide leads.