Asymmetric organocatalytic rearrangement of cyclopropenylmethanols to alkylidenecyclopropanols using chiral phosphoramides

Asymmetric organocatalysis has become a powerful and sustainable approach for the stereoselective construction of complex molecular architectures under mild, metal-free conditions. In this context, highly strained small-ring systems such as cyclopropenes represent attractive yet challenging substrates owing to their pronounced reactivity and intrinsic instability. Cyclopropenylmethanols are particularly versatile intermediates, as they can undergo stereospecific rearrangements leading to alkylidenecyclopropane derivatives of significant interest in organic synthesis. This thesis investigates the use of enantiopure chiral phosphoramides as Brønsted acid organocatalysts for the stereospecific transformation of cyclopropenylmethanols into alkylidenecyclopropanols under metal-free conditions. The work includes the synthesis of selected cyclopropenylmethanol derivatives and a systematic study of their reactivity under organocatalytic activation, with the aim of defining the scope and intrinsic limitations of this transformation. Particular attention is devoted to elucidating how substrate structure and catalyst properties influence reactivity, stability, and stereochemical control in these strained systems. In addition, the challenges associated with the stabilization of alkylidenecyclopropanol products are examined, providing insight into the delicate balance between reactivity and robustness required for practical synthetic applications. Overall, this study contributes to the development of asymmetric organocatalytic methodologies for cyclopropene-based substrates and highlights the potential of chiral phosphoramides in the activation of strained carbocycles under mild conditions.