cyclization compound which gave with tosyl chloride 1,4-anhydro-2,3- O -isopropylidene-5- O -trityl- d -ribitol. The latter was transformed (acid hydrolysis, periodate oxidation, reduction, tritylation, and tosylation) into a ditosylated derivative 16 , which was cyclized into morpholines by the action of primary amines. Acid hydrolysis, followed by acetylation, gives the (2 S )-acetoxymethyl-4-isopropyltetrahydro-1
Easy access to C-glycosides from aldonolactones by a Claisen-type chain-extension reaction
作者:René Csuk、Martin Kühn、Dieter Ströhl
DOI:10.1016/s0040-4020(96)01079-4
日期:1997.1
Chain elongated 2,4-diuloses 2, 4, 6, 9–11, 24, 25 were conveniently obtained from the corresponding aldonolactones 1, 3, 5 by their reaction with carbonyl compounds in the presence of sodium hydride. These hemiacetalic products can be transformed into C-glycosides by deoxygenation with Et3SiH/BF3·Et2O.
Aspects of stereocontrol in the L-Selectride reduction of 4-acyl-1,3-dioxolane derivatives
作者:Jeremy Robertson、William P. Unsworth、Scott G. Lamont
DOI:10.1016/j.tet.2010.01.107
日期:2010.3
application of L-Selectride, either alone or in combination with ZnCl2, to aryl ketones 1, 8 and 11 resulted in highly anti-stereoselective reduction. In contrast, lactols 22 and 23 gave a moderate syn-preference using L-Selectride alone and a high syn-preference in the presence of ZnCl2. Uniquely, high anti- stereoselectivity was observed in the reduction of o-anisyl lactol 37 with L-Selectride alone, which
The total synthesis of the bicyclic C-nucleoside malayamycin A is described starting with D-ribonolactone. A new method was developed to obtain preparatively important quantities of beta-pseudouridine, which was used as an intermediate. The synthesis of a carba N-nucleoside analogue of malayamycin A is also described. (c) 2006 Elsevier Ltd. All rights reserved.