Regioselective Disulfide-Catalyzed Photocatalytic Oxidative Cleavage of 1-Arylbutadienes to Cinnamaldehydes.

This work discloses a simple, efficient, and environmentally benevolent disulfide-catalyzed photocatalytic regioselective oxidative cleavage of 1-arylbutadienes to cinnamaldehydes. This methodology illustrates mild reaction conditions, ambient temperature, excellent regioselectivity, and compatibility with wide range of functional groups (38 examples). The method gains significance, as few reports with limited substrate scope are available for such excellent photocatalytic oxidative cleavage of conjugated dienes.

Advances in Cu and Ni-catalyzed Chan-Lam-type coupling: synthesis of diarylchalcogenides, Ar2-X (X = S, Se, Te).

Organochalcogenides are an important class of compounds encountered in organic synthesis, chemical biology and materials chemistry. The development of the Ar2-S/Se/Te bond formation, mostly in the synthesis of diarylchalcogenides, has garnered considerable attention in recent years. Transition metal catalysis is one of the most used methods for the synthesis of diarylchalcogenides via the traditional cross-coupling strategy. Recently, the Chan-Lam coupling has been valued to be the best alternative for the traditional cross-coupling due to the mild and effective reaction conditions. The review summarizes the strategies adopted for the synthesis of diarylchalogenides (Ar2X, X = S, Se, Te) by Chan-Lam-type coupling using Cu or Ni catalysis and comprises diverse approaches based on different sources of arylsulfur donors like thiols, diaryldisulfides, molecular sulfur, diheteroaryldisulfides and similar sources of Se and Te.

Muricatacin, a Gateway Molecule to Higher Acetogenin Synthesis.

In this review, we have abstracted the various syntheses of acetogenins where the start point has been muricatacin. The latter can best be synthesized in either enantiomer form by the Sharpless method in three steps and can be admired as a gateway molecule for a quick assembly of many higher acetogenins. Muricatacin with orthogonally differentiated hydroxy groups and the available lactone carbonyl for chain elongation/modification can enable the concise synthesis of higher acetogenins. Many closely related synthetic intermediates possible from muricatacin are also abstracted here. The review should give impetus for future synthetic endeavours where the start point could be muricatacin and at least to the new molecules that are yet to be synthesized.

Room temperature nickel-catalyzed cross-coupling of aryl-boronic acids with thiophenols: synthesis of diarylsulfides.

A NiCl2/2,2'-bipyridine-catalyzed cross-coupling of thiophenols with arylboronic acids has been developed for the synthesis of symmetric and unsymmetric diarylsulfides at room temperature and in air. This methodology is reliable and offers a mild and easy to operate process for the synthesis of arylthioethers, which are essential compounds with applications in the pharmaceutical and agricultural industries. This method avoids the use of expensive transition metals, such as Pd, Ir or Rh, sophisticated ligands and elevated temperatures. It also has a wide substrate scope (55 examples) and provides products in good to excellent yields (72-93%).

Iron(III)/O2-Mediated Regioselective Oxidative Cleavage of 1-Arylbutadienes to Cinnamaldehydes.

A simple, efficient, and environmentally benevolent regioselective oxidative cleavage of 1-arylbutadienes to cinnamaldehydes mediated by iron(III) sulfate/O2 has been developed. The reaction offered good yields and excellent regioselectivity and showed good functional group tolerance (31 examples). The method is important, as few reports with limited substrate scope are available for such excellent oxidative cleavage of conjugated dienes.