Stereoselective synthesis of (+)-valienamine starting from the naturally abundant (−)-shikimic acid

Diversification of Simple Arenes into Complex (Amino)cyclitols

Highly oxygenated cyclohexanes, including (amino)cyclitols, are featured in natural products possessing a notable range of biological activities. As such, these building blocks are valuable tools for medicinal chemistry. While de novo synthetic strategies have provided access to select compounds, challenges including stereochemical density and complexity have hindered the development of a general approach to (amino)cyclitol structures. This work reports the use of arenophile chemistry to access dearomatized intermediates which are amenable to diverse downstream transformations. Practical guidelines were developed for the synthesis of natural and non-natural (amino)cyclitols from simple arenes through a series of strategic functionalization events.

Novel Stereoselective Syntheses of (+)-Streptol and (-)-1-epi-Streptol Starting from Naturally Abundant (-)-Shikimic Acid

Novel highly stereoselective syntheses of (+)-streptol and (-)-1-epi-streptol starting from naturally abundant (-)-shikimic acid were described in this article. (-)-Shikimic acid was first converted to the common key intermediate by 11 steps in 40% yield. It was then converted to (+)-streptol by three steps in 72% yield, and it was also converted to (-)-1-epi-streptol by one step in 90% yield. In summary, (+)-streptol and (-)-1-epi-streptol were synthesized from (-)-shikimic acid by 14 and 12 steps in 29 and 36% overall yields, respectively.

Efficient and Highly Stereoselective Syntheses of (+)-proto-Quercitol and (-)-gala-Quercitol Starting from the Naturally Abundant (-)-Shikimic Acid

Efficient and highly stereoselective syntheses of (+)-proto-quercitol and (-)-gala-quercitol starting from the naturally abundant (-)-shikimic acid were described in this article. (-)-Shikimic acid was first converted to the key intermediate by eight steps in 53% yield. It was then converted to (+)-proto-quercitol by three steps in 78% yield and was also converted to (-)-gala-quercitol by five steps in 63% yield. In summary, (+)-proto-quercitol and (-)-gala-quercitol were synthesized from (-)-shikimic acid by 11 and 13 steps in 41 and 33% overall yields, respectively.

Novel stereoselective syntheses of N-octyl-β-valienamine (NOV) and N-octyl-4-epi-β-valienamine (NOEV) from (-)-shikimic acid

N-Octyl-β-valienamine (NOV) 1 and N-octyl-4-epi-β-valienamine (NOEV) 2 are potent chemical chaperone drug candidates for the therapy of lysosomal storage disorders. Novel stereoselective syntheses of NOV 1 and NOEV 2 starting from naturally abundant (−)-shikimic acid are described in this article. The common key intermediate compound 5 was first synthesized from readily available (−)-shikimic acid via 9 steps in 50% yield. Compound 5 was then converted to NOV 1via 5 steps in 61% yield, and it was also converted to NOEV 2via 8 steps in 38% yield. In summary, NOV 1 was synthesized via 14 steps in 31% overall yield; and NOEV 2 was synthesized via 17 steps in 19% overall yield.

Novel stereoselective syntheses of N-octyl-β-valienamine (NOV) 1 and N-octyl-4-epi-β-valienamine (NOEV) 2 starting from naturally abundant (−)-shikimic acid are described in this article.

Production and Synthetic Modifications of Shikimic Acid

Shikimic acid is a natural product of industrial importance utilized as a precursor of the antiviral Tamiflu. It is nowadays produced in multihundred ton amounts from the extraction of star anise ( Illicium verum) or by fermentation processes. Apart from the production of Tamiflu, shikimic acid has gathered particular notoriety as its useful carbon backbone and inherent chirality provide extensive use as a versatile chiral precursor in organic synthesis. This review provides an overview of the main synthetic and microbial methods for production of shikimic acid and highlights selected methods for isolation from available plant sources. Furthermore, we have attempted to demonstrate the synthetic utility of shikimic acid by covering the most important synthetic modifications and related applications, namely, synthesis of Tamiflu and derivatives, synthetic manipulations of the main functional groups, and its use as biorenewable material and in total synthesis. Given its rich chemistry and availability, shikimic acid is undoubtedly a promising platform molecule for further exploration. Therefore, in the end, we outline some challenges and promising future directions.

Biomass-involved synthesis of N-substituted benzofuro[2,3-d]pyrimidine-4-amines and biological evaluation as novel EGFR tyrosine kinase inhibitors

Shikimic acid (1) is a renewable biomass which could be obtained sustainably through natural product isolation or metabolic engineering. Owing to its great potential in chemical conversion, the value-added utilization of this non-grain biomass has received much attention in recent years. Based on the established transformation route from shikimic acid (1) to methyl 3-dehydroshikimate (3-MDHS, 2) and to the multi-functionalized methyl 2-amino-3-cyanobenzofuran-5-carboxylate (3), we disclose a facile and transition metal-free method to access a series of N-substituted benzofuro[2,3-d]pyrimidine-4-amines in 63%-90% yields. The identification of these compounds as EGFR tyrosine kinase inhibitors has also been described. Among them, compound 5h exhibited the most potent inhibitory effect against EGFR tyrosine kinase with an IC₅₀ of 1.7 nM and excellent antiproliferative activity against A431 and A549 cell lines with a GI₅₀ of 5.1 and 12.3 μM, respectively.

Divergent synthesis of new α-glucosidase inhibitors obtained through a vinyl Grignard-mediated carbocyclisation

Four new α-glucosidase inhibitors have been synthesised through 5–8 synthetic steps from a common synthetic intermediate obtained through a recently developed carbocyclisation.