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Intramolecular F⋅⋅⋅HN hydrogen bonds have been utilized for the first time to construct a new series of foldamers from aromatic amides (see picture; R1=H, Me; R2=CON(n‐C8H17)2). Moreover, the resulting crescent and helical architectures are good acceptors for binding dialkylammonium ions.

Abstract-The increase in availability and popularity of mobile wireless devices has lead researchers to develop a wide variety of Mobile Ad-hoc NETworking (MANET) protocols to exploit the unique communication opportunities presented by these devices. Devices are able to communicate directly using the wireless spectrum in a peer-to-peer fashion, and route messages through intermediate nodes, however the nature of wireless shared communication and mobile devices result in many routing and security challenges which must be addressed before deploying a MANET. In this paper we investigate the range of MANET routing protocols available and discuss the functionalities of several ranging from early protocols such as DSDV to more advanced such as MAODV, our protocol study focuses upon works by Perkins in developing and improving MANET routing. A range of literature relating to the field of MANET routing was identified and reviewed, we also reviewed literature on the topic of securing AODV based MANETs as this may be the most popular MANET protocol. The literature review identified a number of trends within research papers such as exclusive use of the random waypoint mobility model, excluding key metrics from simulation results and not comparing protocol performance against available alternatives.Index Terms-AODV, MANET, routing protocols. I. INTRODUCTIONWireless technologies such as Bluetooth or the 802.11 standards enable mobile devices to establish a Mobile Ad-hoc Network (MANET) by connecting dynamically through the wireless medium without any centralised structure [1]. MANETs offer several advantages over traditional networks including reduced infrastructure costs, ease of establishment and fault tolerance, as routing is performed individually by nodes using other intermediate network nodes to forward packets [2], this multi-hopping reduces the chance of bottlenecks, however the key MANET attraction is greater mobility compared with wired solutions.There are a number of issues which affect the reliability of Ad-hoc networks and limit their viability for different scenarios; lack of centralised structure within MANET requires that each individual node must act as a router and is responsible for performing packet routing tasks; this is done using one or more common routing protocols across the MANET [3]. Performing routing tasks requires memory and computation power, however mobile devices feature physical size and weight limitations essential for their mobility, this Manuscript received September 6, 2012; revised December 12, 2012. This work was supported by the University of DerbyThe authors are with the University of Derby, Derbyshire, DE22 1GB, UK (e-mail: A.Hinds1@unimail.derby.ac.uk, eppiemike@aol.com, s.y.zhu@derby.ac.uk, h.al-aqrabi@derby.ac.uk ).reduces the available memory and computational resources as well as limiting battery power.MANETs containing more nodes require greater processing power, memory and bandwidth to maintain accurate routing information; this introduces traffic overhead into the network a...

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Merrilactone A (1, Scheme 1), a complex cage-shaped pentacyclic sesquiterpene, was isolated from pericarps of Illicium merrillianum by Fukuyama and co-workers in 2000. [1] Its structure was established by NMR spectroscopic and X-ray crystallographic analyses, and the absolute configuration was determined by using the Mosher protocol. [1a, 2] In addition to an oxetane moiety, two g lactone functionalities, and a highly substituted cyclopentane ring at its core, this molecule contains seven contiguous chiral centers, including five quaternary ones. Moreover, this sesquiterpene was identified as a nonpeptidal neurotrophic factor that promoted neurite outgrowth in the culture of fetal rat cortical neurons. [1a] Owing to its unique structure as well as the potential officinal value for neurodegenerative diseases, merrilactone A has attracted considerable attention from the synthetic community. [3] So far, Danishefsky, [3a,b] Inoue and Hirama, [3c-e] Mehta, [3f] Frontier, [3g, h] Greaney [3i] and their respective co-workers have accomplished its total or formal syntheses. Relevant synthetic studies have been documented for this natural product. [3j-m] Herein we wish to report a novel and efficient approach to the synthesis of (AE)-1.The Pauson-Khand reaction (PKR) [4] and hetero-Pauson-Khand reaction (h-PKR) [5] have been increasingly applied to the total syntheses of natural products. Having realized an expeditious assembly of (+)-mintlactone through an intramolecular ynal h-PKR, [5c] we have recently completed an efficient total synthesis of (AE)-merrilactone A, further showcasing the power of this key transformation. We envisioned that 1 could be generated from 2 after inversion of the configuration at C7 and dehydration of the tertiary alcohol followed by oxetane formation; [1b] 2 should be accessible from 5 by intramolecular h-PKR (5!4), vinylogous Mukaiyama-Michael reaction [6] (4!3), and SmI 2mediated reductive carbonyl-alkene coupling [7] (3!2; Scheme 1). Finally, ynal 5 could be obtained from the known alcohol 7 [8] through a combined Johnson-Claisen rearrangement [9] and lactonization (7!6) followed by a series of reactions, including an aldol reaction, [10] hydroxyl silylation, and alkene ozonolysis (6!5).Our synthesis started from the known alcohol 7, [8] which was treated with triethyl orthopropionate and propionic acid to afford the Johnson-Claisen rearrangement [9] product 8 (d.r. = 3.8:1), which was desilylated and lactonized to form 6 (d.r. = 2.9:1, 89 % over two steps from 7) in the presence of TsOH . H 2 O (Scheme 2). Sequential treatment of 6 with LDA, Ti(OiPr) 3 Cl, and 3-trimethylsilylpropynal led to a 1:1 mixture of inseparable aldols 9 a and 9 b in 81 % combined yield along with two other isomers (inseparable mixture, 9 % in total). [10] The presence of the methyl and vinyl substituents at C5 does not have a steric influence on the aldol reaction of 6, thus resulting in essentially no facial selectivity on the lactone ring. Nevertheless, 9 a and 9 b were both useful for the subseque...

Cu(ii)-catalyzed aromatic C-H azidation with azido-benziodoxolone under mild conditions has been described. The primary amine exhibits an excellent ortho-directing effect, providing ortho-azidated anilines as the sole products.

Polyfunctionalized beta-fluoropyrrole can be readily prepared from rhodium(II) acetate-catalyzed intramolecular N-H insertion reaction of delta-amino-gamma,gamma-difluoro-alpha-diazo-beta-ketoesters. A cyanomethylene group can be introduced at C-3 of the pyrrole ring through the Wittig reaction of the diazo compounds followed by rhodium(II)-catalyzed intramolecular N-H insertion reactions.

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