Stereoselective Radical Translocations

Abstract

The stereochemical outcome of intramolecular radical mediated hydrogen transfer (= radical translocation) is discussed. Low to excellent levels of stereocontrol are observed making such processes attractive for applications in target-oriented synthesis.

1,n‐Hydrogen‐Atom Transfer (HAT) Reactions in Which n≠5: An Updated Inventory

“…Since then, 1,5-hydrogen-atom transfers have been abundantly investigated and numerous reviews or book chapters have been dedicated to this topic. [3][4][5][6] This progress, accomplished thanks to the fundamental knowledge of these radical reactions, has stimulated the development of elegant radical cascades for the construction of complex molecules. The peculiarity of this review is to focus exclusively on the less common 1,n-HAT reactions with the aim to highlight their specificity, their synthetic potential, and their involvement in some biomimetic mechanisms.…”

Perspectives on parity violation in chiral molecules: theory, spectroscopic experiment and biomolecular homochirality

“…The importance of molecular chirality in chemistry can also be exemplied by three special issues of Chimia over the rst decades of the century. One, in 2001 describing the research of a large chemistry department aer moving to new buildings at the start of the century, 17 where a substantial fraction of the research groups worked on subjects with an essential 'chirality' component [18][19][20][21][22][23][24][25][26][27][28][29][30] (and further research at least also partially on chirality aspects), one in 2008, devoted to the chemistry of chirality, [31][32][33][34][35][36][37][38][39][40] and a last one in 2018 (ref. 41) where we might highlight the work on ultracold chiral molecules, 42 new approaches to the determination of absolute conguration, 43 and work on the CISS effect (chiral induced spin selectivity).…”

“…We should also mention, that eqn (33), which we gave here, because it leads to some instructive insight on the structure of the potential, in actual calculations this has slow convergence of the sum, when carried out numerically in this way. 182,183 In practice one uses an expression from response theory eqn (38), which is known to be equivalent to eqn (33) as established through propagator methods and leads to numerical results with much faster convergence (see ref. 46, 63, 67 and 197 for discussions).…”

“…In Zurich the earliest implementation used electronic wavefunctions (j 0 and j m in eqn (33), for example) from the standard Gaussian program package (see ref. 183 and supplementary material for details), later implementations used linear response theory, eqn (38) with the common Dalton package (see ref. 197 for a description).…”

Preparation of Five-Membered Rings via the Translocation-Cyclization of Vinyl Radicals

“…Recent advances in stereoselective radical translocations have also been reviewed. 45 Malacria and co-workers reported the first example of the translocation-cyclization process of a vinyl radical involving a stereoselective 1,5hydrogen transfer (Scheme 35). In this example, the 5exo-dig cyclization of a (bromomethyl)silyl propargyl ether affords a vinyl radical that stereoselectively abstracts a hydrogen from one of the two diastereotopic methyl groups of an isopropyl substituent.…”