ChemInform Abstract: Mn‐, Fe‐, and Co‐Catalyzed Radical Hydrofunctionalizations of Olefins

Crossley, Steven W. M.; Obradors, Carla; Martinez, Ruben M.; Shenvi, Ryan A.

doi:10.1002/chin.201643209

Cited by 2 publications

(2 citation statements)

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“…61 Along the way, (-)-3-deoxypseudoanisatin (77) was also synthesized by a radical hydration reaction of key alkene 76. 62 Notably the diastereoselectivity of this process was modest. In total, 6-8 oxidations were required to arrive at these compounds and a total of five natural products could be synthesized by this route.…”

Section: Synthetic Entry Into the Pseudoanisatinoidsmentioning

confidence: 98%

Development of a Terpene Feedstock-Based Oxidative Synthetic Approach to the Illicium Sesquiterpenes

et al. 2019

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The Illicium sesquiterpenes are a family of natural products containing over 100 highly oxidized and structurally complex members, many of which display interesting biological activities. This comprehensive account chronicles the evolution of a semisynthetic strategy toward these molecules from (+)-cedrol, seeking to emulate key aspects of their presumed biosynthesis. An initial route generated lower oxidation state analogs, but failed in delivering a crucial hydroxy group in the final step. Insight gathered during these studies, however, ultimately led to a synthesis of the pseudoanisatinoids along with the allo-cedrane natural product 11-O-debenzoyltashironin.A second-generation strategy was then developed to access the more highly oxidized majucinoid compounds including jiadifenolide and majucin itself. Overall, one dozen natural products can be accessed from an abundant and inexpensive terpene feedstock. A multitude of general observations regarding site-selective C(sp 3 )-H bond functionalization reactions in complex polycyclic architectures are reported.

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Section: Synthetic Entry Into the Pseudoanisatinoidsmentioning

confidence: 98%

Development of a Terpene Feedstock-Based Oxidative Synthetic Approach to the Illicium Sesquiterpenes

et al. 2019

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“…Prior syntheses of 1 installed the extremely hindered tert-alkyl, bis-neo-pentyl C8 hydroxyl either by late-stage dihydroxylation with stoichiometric osmium tetroxide (23 °C, 12 hr) 18 ; or by early-stage nitrile anion addition to a tert-butyl ketone, which rendered the synthesis racemic 20 . More recently, the Drago-Mukaiyama hydration has emerged as an effective method to chemoselectively hydrate hindered alkenes through an outer-sphere, metalhydride hydrogen atom transfer (MHAT) mechanism 23 . In this case, application of standard conditions delivered a low-yield of 9 with no diastereoselectivity (Figure 2b, entry 4).…”

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confidence: 99%

Concise asymmetric synthesis of (−)-bilobalide

Baker

Demoret

Ohtawa

et al. 2019

Nature

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The Ginkgo biloba metabolite bilobalide is widely ingested by humans but its effect on the mammalian central nervous system is not fully understood 1,2,3,4. Antagonism of gammaaminobutyric acid A receptors (GABA A Rs) by bilobalide has been tied to rescue of cognitive deficits in mouse models of Down syndrome 5. A lack of convulsant activity coupled with these neuroprotective effects have led some to postulate an alternative, unidentified target. 4 However, steric congestion and the instability of 1 1,2,6 have prevented pulldown of biological targets other than the GABA A Rs. A concise and flexible synthesis of 1 would provide a platform to generate probes for identification of potential new targets; analogs with differential selectivity between insect and human GABA A Rs; and stabilized analogs with enhanced serum half-life 7. Here we exploit the unusual reactivity of bilobalide to affect a late-stage oxidation that symmetrizes the molecular core and allows oxidation states to be embedded in the starting material. The same overall strategy disclosed here may be applicable to G. biloba congeners including the ginkgolides, some of which are glycine receptor (GlyR)-selective antagonists 8. The therapeutic potential of bilobalide and its incompletely understood effects can now be interrogated through chemical synthesis.

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ChemInform Abstract: Mn‐, Fe‐, and Co‐Catalyzed Radical Hydrofunctionalizations of Olefins

Abstract: Review: 476 refs.

Cited by 2 publications

References 1 publication

Development of a Terpene Feedstock-Based Oxidative Synthetic Approach to the Illicium Sesquiterpenes

Development of a Terpene Feedstock-Based Oxidative Synthetic Approach to the Illicium Sesquiterpenes

Concise asymmetric synthesis of (−)-bilobalide

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