Enantioselective Synthesis of (+)-Monobromophakellin and (+)-Phakellin: A Concise Phakellin Annulation Strategy Applicable to Palau'amine

One-Step Synthesis of 2,5-Diaminoimidazoles and Total Synthesis of Methylglyoxal-Derived Imidazolium Crosslink (MODIC)

Here we describe a general method for the synthesis of 2,5-diaminoimidazoles, which involves a thermal reaction between α-aminoketones and substituted guanylhydrazines without the need for additives. As one of the few known ways to access the 2,5-diaminoimidazole motif, our method greatly expands the number of reported diaminoimidazoles and further supports our previous observations that these compounds spontaneously adopt the non-aromatic 4(H) tautomer. The reaction works successfully on both cyclic and acyclic amino ketone starting materials, as well as a range of substituted guanylhydrazines. Following optimization, the method was applied to the efficient synthesis of the advanced glycation end product (AGE) methylglyoxal-derived imidazolium crosslink (MODIC). We expect that this method will enable rapid access to a variety of biologically important 2,5-diaminoimidazole-containing products.

C-H activation: a complementary tool in the total synthesis of complex natural products

The recent advent of transition-metal mediated C-H activation is revolutionizing the synthetic field and gradually infusing a "C-H activation mind-set" in both students and practitioners of organic synthesis. As a powerful testament of this emerging synthetic tool, applications of C-H activation in the context of total synthesis of complex natural products are beginning to blossom. Herein, recently completed total syntheses showcasing creative and ingenious incorporation of C-H activation as a strategic manoeuver are compared with their "non-C-H activation" counterparts, illuminating a new paradigm in strategic synthetic design.