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Toward the Synthesis of Modified Carbohydrates by Conjugate Addition of Propane‐1,3‐dithiol to α , β ‐Unsaturated Ketones
Author(s) -
Valdersnes Stig,
Apeland Ingrid,
Flemmen Guri,
Sydnes Leiv K.
Publication year - 2012
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201200423
Subject(s) - chemistry , dithiol , yield (engineering) , propane , table (database) , carbohydrate , medicinal chemistry , conjugate , organic chemistry , stereochemistry , mathematical analysis , materials science , mathematics , computer science , metallurgy , data mining
Selected 5‐substituted derivatives 4 of 1,1‐diethoxy‐5‐hydroxypent‐3‐yn‐2‐one were treated with propane‐1,3‐dithiol under various conditions. The unprotected hydroxy ketones underwent cyclization during the dithiol addition and gave the corresponding 3‐(diethoxymethyl)‐2‐oxa‐6,10‐dithiaspiro[4.5]decan‐3‐ols 5 in 80–90% yield as the only products ( Scheme 3 and Table 1 ). These products can be regarded as partly modified carbohydrates in the furanose form. When the benzyl‐protected analogues 10‐Bn of the 1,1‐diethoxy‐5‐hydroxypent‐3‐yn‐2‐one derivatives were treated with the same dithiol, however, no cyclization occurred; instead the corresponding 3‐{2‐[(benzyloxy)methyl]‐1,3‐dithian‐2‐yl}‐1,1‐diethoxypropan‐2‐one derivatives 11‐Bn were formed in good yield (up to 99%; Table 4 ). These 1,3‐dithianes were and are in the process of being converted to a number of new carbohydrate analogues, and here are reported high‐yield syntheses of functionalized molecules 17 belonging to the 5,5‐diethoxy‐1,4‐dihydroxypentan‐2‐one family of compounds ( Table 7 ), via 15‐Bn ( Table 5 ) and 16‐Bn ( Table 6 and Scheme 8 ).