Sustainable Approaches for the Protection and Deprotection of Functional Groups.

While functional group tolerance is a critical consideration in synthetic method development, many functional groups often fail to remain intact under diverse reaction conditions. Therefore, the protection of specific functional groups and subsequent deprotection are convenient choices for the efficient and selective synthesis of target compounds, for which the strategies have been securely established. Meanwhile, the development of sustainable synthetic methods, particularly electrochemistry and photochemistry, has recently played a significant role in the field of organic synthesis, and these approaches have proven useful in the methods of functional group protection and deprotection. This review explores electrochemical and photochemical strategies for the protection and deprotection of functional groups, with a focus on their mechanistic diversity, sustainability, and synthetic utility across various functional group classes.