This lecture covers the importance of organic chemistry, focusing on reactive intermediates and their stabilization mechanisms. It begins with a discussion on poisonous compounds found in snowdrops, such as galantamine and lycorine, which can cause severe health issues. The instructor explains how galantamine is used in treating Alzheimer's disease by inhibiting acetylcholinesterase, thus increasing acetylcholine levels. The lecture then transitions to the concept of reactive intermediates, including cations, radicals, and anions, and their stability based on the number of carbon substitutions. The instructor elaborates on the stabilization of these intermediates through inductive effects and resonance structures, emphasizing the role of orbital interactions. The discussion includes the significance of hyperconjugation and the influence of neighboring groups on the stability of carbocations and radicals. The lecture concludes with a summary of the principles of green chemistry and the importance of understanding these concepts for future applications in organic reactions.