Transition-metal-catalyzed carbonylation reaction using chloroform as CO surrogate to synthesize carbonylated heterocyclic moieties.

An approach to expand the diversity of terpenes to novel polycyclic skeletons with contiguous stereogenic centers is described. An unprecedented 8-oxabicyclo[3.2.1]octane motif was obtained in quantitative yield by photoirradiation of zerumbone in the presence of a catalytic amount of Lewis acid. The vital role of light in the isomerization of double bonds in zerumbone, which ensued cyclization via tertiary carbocation intermediate, emulates a biosynthetic route. Synthetic diversification of the phototransformed product afforded epoxy derivatives with up to seven contiguous stereogenic centers and eight-member ring fused tricyclic motifs. The present work sheds light on the possible role of UV irradiation in the biosynthesis of oxo-bridged tricyclic structures from polyene terpenes.Letter pubs.acs.org/OrgLett

BACKGROUND: 'Phytonutrients' have been reported to exert an incredible impact on the healthcare system and offer medical benefits including the prevention or treatment of lifestyle-associated diseases. We chose one of the most common and important plant families, Musaceae, for our present study and explored its antidiabetic potential. RESULTS: Seeds of the edible fruits of Musa balbisianaColla. were investigated for their antidiabetic potential. After estimating the proximate composition, the seeds were extracted with various solvents and evaluated for antidiabetic potential in terms of the inhibition of digestive enzymes, antiglycation activity and in vitro glucose uptake. The acetone extract demonstrated the highest inhibition of -amylase and -glucosidase enzymes with IC 50 values of 36.67 ± 0.367 and 100.61 ± 0.707 g mL -1 , respectively. The extract also exhibited significant glycation inhibition with an IC 50 value of 86.48 ± 0.751 g mL -1 . Furthermore, a major phytochemical, apiforol, was isolated from the acetone extract for the first time, which demonstrated promising -glucosidase inhibition (IC 50 = 48.25 ± 0.255 mol L -1 ), antiglycation property (IC 50 = 114.23 ± 0.567 mol L -1 ) and enhanced glucose uptake in L6 myoblasts. In molecular docking studies, apiforol efficiently bonded to the active sites of -glucosidase enzyme 3A4A. CONCLUSIONS:As dietary intervention is one of the effective strategies for addressing diabetes, special attention is always given to natural food bio-actives or agro-products for better human health. The results of our study suggest that Musa balbisiana has significant potential as an ingredient in health food formulations by reducing postprandial hyperglycaemia.

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A facile Lewis‐acid‐catalyzed method for the synthesis of structurally diverse sesquiterpenoid derivatives from readily available and abundant 11‐membered natural product zerumbone has been developed. Starting from zerumbone, we have developed an efficient cyclization process for the creation of [5.7], [5.8], and [5.8.3] fused‐ring systems. This process was exemplified by the selective functionalization of zerumbone; by controlling the conformation of the 11‐membered ring, the ring‐closing process could be tuned to afford the fused‐ring system of choice.

A diverse approach toward the catalytic regioselective nucleophilic addition of nitrogen heterocycles to Lewis acid activated pentafulvenes has been established. The developed protocol introduces pentafulvenes as nonsymmetrical alkenes for the hydroheteroarylation reaction, providing alkylidenecyclopentenylation at the C-3 position of indoles and the C-2 position of pyrrole.

A palladium-catalyzed aminocarbonylation strategy exploiting chloroform as a CO source has been developed for the synthesis of biologically potent 2-amidoimidazopyridine scaffolds. The aminocarbonylation reaction was found to be general with a range of amines and substituted imidazopyridines. Preliminary biological evaluation of cytotoxicity on selected examples provides scope for future investigations.

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