Diastereo- and Enantioselective Synthesis of Pyrrolo[1,4]benzodiazepines through Decarboxylative Photocyclization

Abstract

Memory of chirality in triplet 1,7‐diradicals was detected for the first time and to a remarkably high degree in the decarboxylative photocyclization of the proline derivative of N‐phthaloyl anthranilic acid 1 into 2 (X=H: 45 % yield, 86 % ee; X=Cl: 50 % yield, 79 % ee).

The Same and Not the Same: Chirality, Topicity, and Memory of Chirality

“…Memory of chirality in triplet biradical chemistr y (17). Memory of chirality in triplet biradical chemistr y (17).…”

Sustainable chemistry: starting points and prospects

“…The minimisation requirement in terms of energy refers not only to optimising a synthesis carried out at a generally high energy level, but also looks at alternatives to providing energy by heating, such as photochemistry, electrochemistry or microwave technology to carry out reactions (for examples of sustainable photochemistry, see Griesbeck et al 2001 and references cited therein; on sustainable electrochemistry, see Steckhahn et al 2001; on alternative technologies such as microwave and other methods, see Nüchter et al 2000). However, sufficiently broad energy balances should be employed here in order to demonstrate that such technologies actually lead to net energy savings.…”

Photodecarboxylation of Adamantane Amino Acids Activated by Phthalimide

“…[29,30] The PET-promoted decarboxylation by phthalimides has been used in macrocyclizations, [31] the cyclization of peptides, [32,33] photodecaging strategies, [34] and the enantioselective synthesis of benzodiazepines. [35] Moreover, photoinduced decarboxylation has been applied to the addition of acetates, [36,37] benzyl groups, [38][39][40] and α-amino acids to phthalimide [41] as well as to the formation of cyclic aryl ethers, [42] the sensitization conditions (with quantum yields, Φ = 0.02-0.5) than upon direct excitation, and the reactivity was dependent on the chain length (intramolecular distance) between the electron donor (carboxylate) and acceptor (phthalimide in the triplet excited state) of the derivative. The formation of different radicals, that is, the 1-or 2-adamantyl intermediate, probably does not affect the overall rate of the decarboxylation This current report provides a better understanding of photodecarboxylation and the rational design of molecular systems to undergo photoinduced decarboxylation and cyclization reactions.…”