Syntheses of buergerinin F (1) and buergerinin G (2) were carried out to establish the absolute stereochemistry of these natural products. A linear sequence was used to synthesize 1 in 15 steps and 9% overall yield from thymidine. Subsequent oxidation of 1 with ruthenium tetroxide afforded 2 in 77% yield.

The first total synthesis of (+)-serratezomine A is described. Key aspects of the synthesis include a) the first deployment of free radical-mediated vinyl amination -an intramolecular alkyne aminostannation -in a complex target synthesis, b) the use of a β-stannyl enamine as the lynchpin for convergent assembly of the natural product backbone, c) the use of an oxidative allylation promoted by cerium(IV) (CAN) to establish the all carbon quaternary chiral center with the proper configuration, and d) an intramolecular substitution reaction to form the sensitive bridging lactone. Overall, 15 steps (longest linear sequence) are required to prepare the natural product from a commercially available aldehyde, and assembly of the contiguous array of six stereocenters is accomplished with high stereocontrol.The Lycopodium alkaloids have provided some of the most intricately structured and stereochemically dense specimens among naturally occuring small molecules. 1 The attendant challenge for chemical synthesis, often combined with their promise as potential therapeutics, has led to broad interest in the total chemical synthesis of these targets. 2 Recent reports have detailed rather concise preparations of (−)-fawcettimine, 3 (+)-fawcettidine, 4 (−)-lycopodine, 5 lyconadin A and B, 6 and (−)-cernuine. 7,8 Importantly, valuable new chemical methods have been developed in nearly every case to solve specific synthetic challenges while also avoiding synthetic routes that would not address the important issue of supply. E-mail: jeffrey.n.johnston@vanderbilt.edu. Supporting Information Available: Preparations, spectral data, and structure elucidation for key intermediates. This material is available free of charge via the Internet at http://pubs.acs.org. Kobayashi isolated (+)-serratezomine A (1, as its trifluoroacetic acid salt) as part of a search for new therapeutics from the club moss L. serratum, from which the huperzine alkaloids were isolated. 9 The polycyclic structure merges a 5,6-fused ring system (an indolizidine) with a 6,6-spirocyclic ring and a bridging lactone. Kobayashi found that the lactone is subject to isomerization from O13 to O8, resulting in the thermodynamically favored fused γ-lactone. 10 Among the six contiguous stereogenic carbons, the axial alcohol at C8 -absent from the natural products listed above -sterically impinges upon the spirocyclic piperidine through a 1,3-diaxial interaction. Finally, all but two of the stereochemical elements overlap with a bridgehead or bicyclic union. We anticipated that these challenges might provide an opportunity to develop new chemistry to meet the goal of a convergent synthesis. In this Communication, we describe these developments in the context of the first total synthesis of (+)-serratezomine A. NIH Public AccessOur solution to the problem of convergency rested on the hypothesis that an exocyclic enamine of general type A (Figure 1), an unsaturated 2-methyl pyrrolidine, could provide a multiply nucleophilic C12 and serve as the synthesis lynchpin. The f...

Serratezomine A is a member of the structurally diverse class of compounds known as the Lycopodium alkaloids. The key supporting studies and successful total synthesis of serratezomine A are described in this account. Significant features of the synthesis include the first application of free radical mediated vinyl amination and Hwu’s oxidative allylation in a total synthesis, and an intramolecular lactonization via a transannular SNi reaction. Minimal use of protecting groups and the highly diastereoselective formation of a hindered, quaternary stereocenter using an umpolung allylation are also highlights from a strategy perspective. Observation of quaternary carbon epimerization via a retro-Mannich/Mannich sequence highlights the additional challenge presented by the axial alcohol at C8 in serratezomine A.

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Objectives The purpose of this case is to report the effect of Korean Medicine, especially Electro-acupuncture on strabismus of traffic accident induced abducens nerve paralysis. Methods Patient received Korean Medicine treatment such as acupuncture, electro-acupuncture & Herb-medicine. Patienst was treated with the electro-acupuncture at Right eye paralytic lateral rectus muscle lesions. The case was enforced 10 minutes using the PG-306 electro-acupuncture and applyed the low consequence wave of 1-8Hz. The improvement of the strabismus was observed. Results During ten weeks of treatment, patient's strabismus and diplopia were improved. Conclusions In this case, Electro-acupuncture on strabismus and diplopia of traffic accident induced abducens nerve paralysis was effective. The effectivity is depended on the time stimulation is performed. (J Korean Med Rehab 2015;25(3):111-117)