CO‐Preserving Photoinduced Transfer of Cymantrenyl Moiety: a Tandem Experimental and Computational Investigation

Abstract

Cyclopentadienyl manganese tricarbonyl (cymantrene) is known to undergo photochemical reactions by releasing one of its CO ligands. Here we present the first example of a photorearrangement of a cymantrenylmethyl fragment, where it retains all its three CO ligands. A tandem experimental and DFT (density functional theory)-based computational investigation allows us to explain this unexpected behavior: the rearrangement, indeed, begins with the release of one CO ligand, but cage effect of the solvent captures this CO molecule, allowing it to rapidly reattach once the rearrangement takes place.

Formation of a Disulfide Bridge on the Resin during Solid-Phase Synthesis of Terlipressin: Influence of the Boc-Protected and Free N-Terminal Amino Group

“…The closure of the disulfide bridges on the resin allows this reaction to be carried out in very concentrated solutions: ∼100-fold with respect to resin-free cyclization. In this case, the polymer molecules form a three-dimensional dynamic matrix in the solution, where cyclization takes place inside individual cages, leading to the greatly enhanced cage effect 26 and, as a result, pseudodelution effect. 17 Hence, while cyclization in the solution requires ∼1 L of solvent per 1 g of the linear precursor, on-resin cyclization proceeds in high yields, using only 0.01 L of solvent per 1 g of the linear precursor.…”