This study tests the hypothesis that collective descriptive representation has important benefits for strengthening and legitimizing democratic society. Specifically, we test whether increased proportions of collective female descriptive representation in the statehouse and the presence of a female state executive are important to female citizens' attitudes toward government responsiveness, or external efficacy. We hypothesize that an increase in female collective descriptive representation in the legislative and state executive branches of government will increase female citizens' external efficacy but will be unimportant to males. We pooled American National Election Studies (ANES) data from 1988 to 1998 and used ordered probit techniques to test the hypothesis. In addition to our main independent variable of interest, our model includes state political culture, dyadic descriptive representation, dyadic substantive representation, sociodemographics, political participation, strength of partisanship, and electoral dummy variables as controls. Our results confirm that higher levels of collective female descriptive representation promote higher values of external efficacy for female citizens, suggesting that collective female descriptive representation has important benefits to a democratic society. E xternal political efficacy is the individual perception that governmental authorities and institutions are responsive to citizen influence

The chemoselective synthesis of amides by decarboxylative couplings of alpha-ketoacids and isoxazolidines makes possible an iterative approach to poly-beta3-peptides. Peptide assembly occurs under aqueous conditions and requires no coupling reagents. The requisite isoxazolidine monomers are prepared in enantiopure form by a convenient two-step protocol starting from the appropriate aldehydes.

A versatile method for the synthesis of enantiomerically pure isoxazolidine monomers for the synthesis of β3‐oligopeptides via α‐keto acidhydroxylamine (KAHA) ligation is presented. This one‐pot synthetic method utilizes in situ generated nitrones bearing gulose‐derived chiral auxiliaries for the asymmetric 1,3‐dipolar cycloaddition with methyl 2‐methoxyacrylate. The resulting enantiomerically pure isoxazolidine monomers bearing diverse side chains (proteinogenic and non‐proteinogenic) can be synthesized in either configuration (like‐ and unlike‐configured). The scalable and enantioselective synthesis of the isoxazolidine monomers enables the use of the synthesis of β3‐oligopeptides via iterative α‐keto acidhydroxylamine (KAHA) ligation.

The synthesis of an enantiopure isoxazolidine monomer for the incorporation of β 3 -apartic acid residues into β 3 -oligopeptides via chemoselective α-ketoacid-hydroxylamine amide formation. This route involves nitrone cycloaddition of 3-thiophenylpropanal and circumvents limitations of other potential starting materialsWe have recently reported a highly chemoselective amide-bond forming reaction between α-ketoacids and hydroxylamines. i In addition to its potential for the fragment coupling of unprotected α-peptide fragments, we have explored its application to the iterative, aqueous synthesis of oligo-β 3 -peptides, ii an exciting class of peptidomimetics of contemporary interest in medicinal and bioorganic chemistry. iii Our novel approach to the synthesis of these oligopeptides takes advantage of the chemoselective coupling of a growing β-peptide chain with chiral isoxazolidines. The amide formation results in N-O bond cleavage and the formation of an α-ketoester. Following hydrolysis, the chain is poised for iterative elongation (Scheme 1). The key amide forming reaction requires no reagents, produces only carbon dioxide and methanol as byproducts (Scheme 2), and operates in the presence of unprotected functional groups including amines and carboxylic acids. As such, it offers great potential as an alternative route to the preparation of β-oligopeptides that circumvents challenges of the established methods including difficult couplings and deprotections in longer β-peptide chains and improved access to the requisite β-peptide monomers.The major challenge to the widespread adoption of this method for β 3 -peptide synthesis is the need to prepare the isoxazolidine monomers as single enantiomers. We have reported the use of Vasella's mannose-derived nitrones iv as chiral auxiliaries for their asymmetric synthesis via 1,3-dipolar cycloaddition with 2-methoxymethacrylate (Scheme 3). Following purification of the cycloadducts and removal of the auxiliary, the desired isoxazolidine monomers are obtained, in most cases, in enantiomerically pure form. This approach has proven successful for the synthesis of isoxazolidine monomers bearing most of the common amino acid sidechains, including those found in leucine, valine, phenylalanine, lysine, glutamic acid, glycine, and numerous others. Unfortunately, this procedure fails for the most logical synthetic *Corresponding author. Tel.: +1-215-573-1953; e-mail: bode@sas.upenn.edu. Supplementary MaterialExperimental procedures, characterization data, and 1 H and 13 C NMR spectra for all new compounds.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply...

Iterative, Aqueous Synthesis of β 3 -Oligopeptides Without Coupling Reagents. -Isoxazolidine acetals (V) and (XX) are prepared either in optically active form (>99% e.e.) using the D-mannose derived hydroxylamine auxiliary (III) or in racemic form using the oxime (XVIII). The syntheses take advantage of Vasella's diastereoselective nitrone cycloaddition protocol that is extended to the reaction with methyl 2-methoxyacrylate (II). The isoxazolidines undergo facile peptide couplings with α-ketoacids such as (VI) in the absence of coupling reagents to give the amides (VII) or (XXI) possessing a new α-keto methyl ester functionality. Saponification offers the route to iterative peptide couplings to give a series of di-and tripeptides such as (IX). Their last terminal ketoester group of which can be directly converted into the corresponding acid (X) by oxidative decarboxylation. The amide formation is chemoselective as is shown in the reactions of (XI) or (XIV). -(CARRILLO, N.; DAVALOS, E. A.; RUSSAK, J.