Organic Letters最新文献

Readily synthesized bench-stable glycosyl dithioimidocarbonates are useful C-glycoside precursors. Under mild photochemical conditions, these glycosides undergo desulfurative glycosyl radical generation in the presence of weak acid, 4CzIPN, and Hantzsch ester. These radicals perform well in Geise-like reactions to yield C-glycosides with high stereoselectivity.

A variety of polycyclic benzazepines were rapidly constructed by NHC-catalyzed regioselective redox-neutral intramolecular tandem cyclization. Initial mechanistic studies revealed that a SET radical process was possibly involved.

Ganoderma meroterpenoids are fungal derived hybrid natural product class containing a 1,2,4-trisubstituted benzene ring and a polycyclic terpenoid part. The representatives applanatumol E, H and I, lingzhilactone B, and meroapplanin B share the same bicyclic lactone moiety connected to the arene. Employing photo-Fries rearrangements as the key step enabled a general entry to these natural products. For the synthesis of the tetracyclic framework of lingzhiol, we made use of a powerful photoredox oxidative decarboxylation/Friedel-Crafts sequence.

A catalytic method for the introduction of pharmaceutically meaningful fluorinated propionic acid side chains into aromatic compounds is presented. In the presence of rhodium catalyst [RhCp*Cl₂]₂, various arylboronic acids are efficiently coupled with an easy-to-access diazoester reagent to give perfluorinated derivatives of phenylpropionic acids, including top-selling profen drugs. The key advantage of this approach is that the pharmacophore is introduced as a whole and is compatible with various functionalities and drug discovery.

We present here a novel paired electrocatalysis-enabled convenient synthesis of the (E)-vinyl sulfoximines through the cross-coupling reaction of sulfinamides and olefins. This protocol showed a broad substrate scope and excellent E selectivity of products under metal- and oxidant-free conditions. A preliminary mechanistic study suggested that fluorinated sulfoximine generated from anodic oxidation of sulfinamide was the key intermediate that was then converted into the sulfonimidoyl radical at the cathode with the help of DBU in this reaction.

More than 450 drugs containing a carboxylic acid functional group have been marketed worldwide. Herein, we report a concise and environmentally friendly organic photoinduced protocol for the interconversion of carboxylic acids into their bioisosteres. With this strategy, a variety of substrates, including alkyl, (hetero)aryl, and alkenyl acids, as well as various biologically relevant acids are successfully converted into primary sulfonamides.

Owing to their diverse biological activities and versatility as synthetic precursors, organoselonocyanes categorize themselves as vital compounds. However, a limited reagent pool restricts their utility. In the present work, alkyl selenocyanates are hereby established as new bifunctional reagents for the simultaneous transfer of an alkyl group in addition to -SeCN. These reagents, when merged with photocatalysis, provide a key to accessing organoselenocyanates from feedstock olefins in an efficient and atom-economic fashion. A route to the analogous isoselenocyanate isomers facilitated by Lewis acid catalysis is also reported, presenting a divergent strategy for accessing both ambident isomers of -SeCN in an efficient manner.

Herein, we evolve a base-promoted synthesis of 2H-chromen-2-one and chromeno[2,3-c]pyrrole scaffolds via (4 + 2) annulation of α-alkylidene succinimides with 2-hydroxyphenyl-substituted para-quinone methides (p-QMs). Extremely selective and switchable cyclizations were obtained by modifying the base. This metal-free protocol is highlighted by its mild reaction conditions and broad substrate scope, and the viability of the existing protocol was additionally illustrated by gram-scale synthesis and further modification. Several control experiments were performed to understand the reaction mechanism.

We disclose a general 2-step synthesis of electron-poor 1,4- and 1,1,4-substituted buta-1,3-dienes bearing electron-withdrawing substituents at both termini of the conjugated system. The method relies on a base-promoted C-allylation of primary or secondary alkylsulfones with γ-bromocrotonate or related amide, nitrile, or sulfone and subsequent vinylogous retro-Michael dehydrosulfinylation. The geometry of the resulting dienes is substrate-dependent, and predominantly E,E-dienes are formed from E-electrophiles. This phosphorus- and transition-metal-free method tolerates a variety of functionalities and could serve as a supplement to Wittig, HWE, and Julia olefinations.