01747nas a2200169   4500008004100000022001400041245018900055210006900244260007100313300001400384490000700398520099300405100001801398700001501416700001901431856012701450       2005                        eng d  a0022-326300aDiastereoselective and general route to 5-amino-5-deoxysugars: influence of C-3 substitution on the addition of amines to C-5 of vinyl sulfone-modified Hex-5-enofuranosyl carbohydrates0 aDiastereoselective and general route to 5amino5deoxysugars influ  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP  a8047-80540 v703 a<p>In the synthesis of vinyl sulfone-modified hex-5-enofuranosides, the E/Z ratios of the products are influenced by the stereoelectronic property of a group present at the C-3 position. This observation has been utilized to influence the diastereoselectivity of addition of amines to C-5 of vinyl sulfone-modified hex-5-enofuranosides, which are efficient Michael acceptors. The stereoelectronic effect of OMe attached to the beta-face of C-3 (gluco derivative) is sufficient to impose diastereoselectivity overwhelmingly in favor of L-ido-aminosugars when the Michael acceptor is reacted with both primary and secondary amines. 3-O-Benzylated gluco derivative is also effective in producing L-ido-aminosugars but only in reactions with primary amines. The selectivity is lost when an allo derivative with OBn at the alpha-face of C-3 is used. Selected products were desulfonated to establish this new approach as a general and versatile strategy for accessing 5-amino-5-deoxysugars.</p>1 aDas, Indrajit1 aPathak, T.1 aSuresh, C., G.  uhttps://library.ncl.res.in/content/diastereoselective-and-general-route-5-amino-5-deoxysugars-influence-c-3-substitution-001657nas a2200241   4500008004100000022001400041245019300055210006900248260009900317300001400416490000800430520060900438653001701047653002101064653004101085653004001126653004101166100001801207700003001225700002101255700002001276856011901296       2008                        eng d  a0008-621500aUnusual addition of amines to C-2 of vinyl sulfone-modified-beta-D-pent-2-enofuranosyl carbohydrates: synthesis of a new class of beta-anomeric 2-amino-2,3-dideoxy-D-threo-pentofuranosides0 aUnusual addition of amines to C2 of vinyl sulfonemodifiedbetaDpe  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcJUN  a1287-12960 v3433 a<p>When 3-C-sulfonyl-pent-2-enofuranosides and 3-C-sulfonyl-hex-2-enofuranosides were reacted with primary and secondary amines, only the beta-anomeric methoxy group of the pent-2-enofuranoside did not cause any hindrance to incoming nitrogen nucleophiles. This resulted in the `unusual' addition of amines, in which the diastereoselectivity of the reaction was overwhelmingly in favor of amino sugars of the D-arabino configuration. Selected products were desulfonylated to obtain a new class of beta-anomeric 2-amino-2,3-dideoxy-D-threo-pentofuranosides. (C) 2008 Elsevier Ltd. All rights reserved.</p>10aamino sugars10adeoxyaminosugars10adesulfonylation with Mg-MeOH-NiBr(2)10adiastereoselective Michael addition10avinyl sulfone-modified carbohydrates1 aDas, Indrajit1 aSuresh, Cheravakkattu, G.1 aDecout, Jean-Luc1 aPathak, Tanmaya  uhttps://library.ncl.res.in/content/unusual-addition-amines-c-2-vinyl-sulfone-modified-beta-d-pent-2-enofuranosyl-0