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Non‐Classical Epimerisation of (1 S ,2 S ,3 S ,4 R ,5 R )‐1‐ O ‐Methylcyclohexane‐1,2,3,4,5‐pentol
Author(s) -
Frank Michael,
Miethchen Ralf,
Reinke Helmut
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199905)1999:5<1259::aid-ejoc1259>3.0.co;2-n
Subject(s) - chemistry , sodium methoxide , trifluoroacetic acid , acetal , moiety , derivative (finance) , methylcyclohexane , trifluoroacetic anhydride , benzaldehyde , aqueous solution , organic chemistry , methanol , stereochemistry , medicinal chemistry , toluene , catalysis , financial economics , economics
Methoxycyclitol 4 was acetalized in a non‐classical one‐pot procedure with chloral/dicyclohexylcarbodiimide forming the 4‐ epi derivative 6 . The stepwise deprotection of compound 6 is also described. Thus, decarbamoylation to the acetal 7 was achieved by heating 6 with methanolic sodium methoxide, and cleavage of the acid‐stable trichloroethylidene moiety was realised in two steps via the corresponding ethylidene acetals 8 and 9 ; the ethylidene function was removed with aqueous trifluoroacetic acid (compound 10 from 6 via 9 ). Finally, the carbamoyl derivative 10 was converted into the tetra‐ O ‐acetyl product 12 via the tetrol 11 .