Samarium metal and samarium diiodide have become important tools as selective cyclopropanating agents in organic synthesis due to their high chemo- and stereoselectivity. Therefore, Sm and SmI₂ are the ideal reagents to prepare cyclopropane derivatives. This tutorial review highlights C–C multiple bond cyclopropanation processes promoted by samarium or samarium diiodide.

The development of methodologies for the formation of carbon–carbon double bonds could be considered one of the most important challenges in organic synthesis. To this end, β-elimination reactions in 1,2-difunctionalised substrates have been one of the most important means of generating CC bonds. This review is intended to highlight the use of SmI₂ in β-elimination procedures, such that the organization of this revision highlights conventional β-elimination processes which are promoted by samarium diiodide. The synthetic applications of SmI₂ will be covered, and 1,2-elimination reactions which are involved in sequential reactions promoted by samarium diiodide, will also be illustrated. These methodologies along with the more recent developments in the area are discussed in this tutorial review.

The 1,3-butadiene motif is widely found in many natural products and drug candidates with relevant biological activities. Moreover, dienes are important targets for synthetic chemists, due to their ability to give access to a wide range of functional group transformations, including a broad range of C-C bond-forming processes. Therefore, the stereoselective preparation of dienes have attracted much attention over the past decades, and the search for new synthetic protocols continues unabated. The aim of this review is to give an overview of the diverse methodologies that have emerged in the last decade, with a focus on the synthetic processes that meet the requirements of efficiency and sustainability of modern organic chemistry.

Conjugate addition of lithium (S)-N-benzyl-N-α-methylbenzylamide to a range of α,β-unsaturated Weinreb amides proceeds with high levels of diastereoselectivity (>95% de). The β-amino Weinreb amide products may be transformed into β-amino ketones via reactions with Grignard reagents, while treatment with DIBAL-H furnishes β-amino aldehydes. Trapping of the aldehyde via Wadsworth–Emmons reaction and subsequent manipulation offers an efficient route to homochiral δ-amino acid derivatives and 2-substituted piperidines. The application of this methodology for the synthesis of (S)-coniine is demonstrated.