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Enantiospecific Total Synthesis of (−)‐ D ‐Noviose
Author(s) -
Pankau Wolf Matthias,
Kreiser Wolfgang
Publication year - 1998
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/(sici)1522-2675(19981111)81:11<1997::aid-hlca1997>3.0.co;2-v
Subject(s) - chemistry , lactol , regioselectivity , ether , protecting group , moiety , stereochemistry , pyranose , hemiacetal , derivative (finance) , lactone , medicinal chemistry , organic chemistry , alkyl , financial economics , economics , catalysis
(−)‐ D ‐Noviose ((−)‐ 22 ), a rare sugar, was synthesized starting from the optically active building block (−)‐ 1 in seven steps. The first step of this route, the introduction of a methyl‐ether group under Lewis ‐acidic conditions, left the acetoxy group untouched and thereby preserved the absolute configuration in the product 2 ( Scheme 2 ). Next, the double bond of methyl ether 2 was cis ‐dihydroxylated leading selectively to 3 . After saponification of the acetoxy group of 3 the two vicinal cis OH groups of 17 were selectively protected as the cyclic carbonate 18 ( Scheme 4 ). This kind of protection was essential to achieve the proper regioselectivity in the Baeyer‐Villiger rearrangement of the cyclopentanone derivative 19 that was obtained after oxidation of the remaining OH group of 18 . Lactone 20 was the major product of this rearrangement. Final reduction to the corresponding lactol (cyclic hemiacetal) with diisobutylaluminium hydride (DIBAH) at low temperature was accompanied by reductive cleavage of the protecting cyclic carbonate moiety thereby leading directly to (−)‐ D ‐noviose ((−)‐ 22 ).