Natural products have long served as inspirations and testing grounds for new synthetic methodologies and strategies. They are also valuable sources for lifesaving drug molecules. This talk will highlight elements of our recent efforts in developing novel strategies and methodologies for divergent and efficient synthesis of medicinally important natural products. Particular emphasis will be placed on two research projects. One will focus on our discoveries of tandem catalytic carbonylation reactions for the total syntheses of macrolides and spirocyclic natural products. In these syntheses, cheap and abundant carbon monoxide was used as a one-carbon linchpin to stitch relatively simple starting materials into complex structures, which significantly increased synthetic efficiency. The other one will focus on our recent synthesis of polycyclic diterpene molecules via tandem gold catalysis. Preliminary biological evaluations of some of our target molecules will be discussed as well.