Synthesis and structural study of 5-nitro-6-(penta-O-acetylpentitol-1-yl)norbornenes

被引:10
作者
Galan, E. Roman
Hodgson, Derek J.
Yokomori, Yoshinobu
Eliel, Ernest L.
Martinez, M. Bueno
机构
[1] Univ Extremadura, Fac Ciencias, Dept Quim Organ, E-06071 Badajoz, Spain
[2] Univ N Carolina, Chem Labs, Chapel Hill, NC 27514 USA
[3] Natl Def Acad, Dept Chem, Yokosuka, Kanagawa 239, Japan
关键词
D O I
10.1016/0008-6215(88)80083-1
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Uncatalyzed reaction between cyclopentadiene and (E)-3,4,5,6,7-penta-acetoxy-1-nitrohept-1-enes having the D-manno, D-galacto, and D-gluco configurations at C-3-C-7 led, in each case, to the four stereoisomeric 5-nitro-6-(1,2,3,4,5-penta-O-acetylpentitol-1-yl) bicyclo[2.2.1]hept-2-enes. Face selectivity is discussed in terms of the sugar-chain configuration. The structures assigned the adducts are based on their n.m.r. spectra, and, in the case of the D-manno compounds, on X-ray data. Also described are the C-13-n.m.r. spectra of the starting nitroalkenes. The crystal structures of (5S,6S)1,2,3,4,5-penta-O-acetyl-1-C-(5-exo-nitro-bicyclo[2.2.1]hept-2-en-6-endo-yl-D-manno-pentitol (3a) and (5S,6S)1,2,3,4,5-penta-O-acetyl-1-C-(5-endo-nitrobicyclo[2.2.1]hept-2-en-6-exo-yl-D-manno-pentitol (5a) were determined from three-dimensional, X-ray data. Crystals of 3a are monoclinic, space group P2(1), with two molecules in a cell of dimensions a = 9.054(3), b = 15.580(11), c = 10.138(4) angstrom, beta = 116.27(3)degrees. The structure was refined to an R-factor of 0.050 on the basis of 1485 observations. Crystals of 5a are triclinic, space group P1, with one molecule in a cell of dimensions a = 8.680(4), b = 9.760(4), c = 8.695(7) angstrom, alpha = 98.69(5), beta = 103.13(5), gamma = 112.09(3)degrees. The structure was refined to an R-factor of 0.074 based on 970 observations.
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页码:263 / 276
页数:14
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