n-Bu4NI/K2S2O8 Mediated Csp2-Csp2 Bond Cleavage - Transformylation from p-Anisaldehyde to Primary Amides

n-Bu4NI/K2S2O8 mediated transformylation from p-anisaldehyde to primary amides is reported. The mechanistic studies suggest the reaction occurs via a single electron transfer pathway. Based on the DFT electronic structure calculations of various reaction pathways, the most plausible mechanism involves the formation of a phenyl radical cation and an arenium ion as the key intermediates. It represents the first example where p-anisaldehyde is employed as a formyl source via a non-metal mediated Csp2-Csp2 bond cleavage.

Coordinating activation strategy enables 1,2-alkylamidation of alkynes

The radical 1,2-difunctionalization reaction of alkynes has been evolved into a versatile approach for expeditiously increasing the complexity of the common feedstock alkyne. However, intermolecular 1,2-carboamidation with general alkyl groups is an unsolved problem. Herein, we show that a coordinating activation strategy could act as an efficient tool for enabling radical 1,2-alkylamidation of alkynes. With the employment of diacyl peroxides as both alkylating reagents and internal oxidants, a large library of β-alkylated enamides is constructed in a three-component manner from readily accessible amides and alkynes. This protocol exhibits broad substrate scope with good functional group compatibility and is amenable for late-stage functionalization of natural molecules and biologically compounds.

An NHC-Stabilised Phosphinidene for Catalytic Formylation: A DFT-Guided Approach

In recent years, the applications of low-valent main group compounds have gained momentum in the field of catalysis. Owing to the accessibility of two lone pairs of electrons, NHC-stabilised phosphinidenes have been found to be excellent Lewis bases; however, they cannot yet be used as catalysts. Herein, an NHC-stabilised phosphinidene, 1,3-dimethyl-2-(phenylphosphanylidene)-2,3-dihydro-1H imidazole (1), for the activation of CO₂ is reported.A closer inspection of the CO₂ activation process by DFT calculations along with intrinsic bond orbital analysis shows that phosphinidene is associated with phenylsilane through a noncovalent π-π interaction between two phenyl rings which activates the Si-H bond facilitating hydride transfer to the CO₂ molecule. Detailed DFT studies along with spectroscopic experiments were combined to understand the mechanism of CO₂ activation and its catalytic reductive functionalisation leading to the formylation of a range of chemically inert primary amides under mild reaction conditions.

Stereoselective synthesis of novel antiproliferative steroidal (E, E) dienamides through a cascade aldol/cyclization process

The stereoselective and metal-free protocol involving a cascade aldol/cyclization process for the synthesis of steroidal (E, E) dienamides from steroidal α, α-dicyanoalkene was reported. This protocol efficiently achieved the construction of C=C bond and selective conversion of cyano group into carboxamide in one-pot procedure under mild condition. Further biological evaluation showed that some of these compounds had moderate to excellent cytotoxic activities against all the tested cancer cell lines and were more potent than well-known drug 5-fluorouracil. Particularly, compound 3c represented excellent inhibitory effect against MCF-7 (IC50=0.76 μM), which was about 10-fold more potent than 5-fluorouracil.

Fast and flexible synthesis of pantothenic acid and CJ-15,801

The fast and efficient syntheses of pantothenic acid and the antiparasitic agent CJ-15,801 have been achieved starting from a common imide unit through the selective manipulation of enamide intermediates.