Racemic dimethyl 4-methoxy- (11 and 12), diallyl 4-allyloxy- (13 and 14) and dimethyl 4-(ethylsulfanyl)-2-hydroxycyclopentane-1,1-dicarboxylates (15 and 16) were prepared by base-catalyzed addition of methanol, allyl alcohol and ethylsulfane, respectively, to dimethyl (4-oxobut-2-en-1-yl)malonate (6). Deallylation of 13 and 14 afforded 4-hydroxycyclopentanes 27 and 28. Reduction of 11-16 with lithium aluminium hydride gave the corresponding 4-substituted 2,2-bis(hydroxymethyl)cyclopentanols. Dimethyl (2S,3S,4R)-, (2R,3S,4R)-3-benzyloxy-4-formyloxy-2-hydroxycyclopentane-1,1-dicarboxylates (35, 36) and dimethyl (2S,3S,4R)-, (2R,3S,4R)-3-benzyloxy-2-benzoyloxy-4-methoxycyclopentane-1,1-dicarboxylates (39, 40) were synthesized starting from D-glucose. Reduction of dimethyl cyclopentane-1,1-dicarboxylates 39 and 40 with lithium aluminium hydride, benzoylation of the formed hydroxy derivatives, hydrogenolysis of benzyl groups, conversion of the liberated hydroxy groups into dithiocarbonates and their reduction with tributylstannane afforded, after removal of the protecting groups, (2R,4R)-1,1-bis(hydroxymethyl)-4-methoxycyclopentan-2-ol ((2R,4R)-17) and (3R,4R)-1,1-bis(hydroxymethyl)-4-methoxycyclopentan-3-ol (51). Reduction of a mixture of esters 35 and 36 gave (2R,3R)-2-benzyloxy-5-(hydroxymethyl)hexane-1,3,6-triol (52) as the major product and (2R,3S,4R)-3-benzyloxy-1,1-bis(hydroxymethyl)cyclopentane-2,4-diol (53) as the minor product. The latter was converted into (3R,4R)-1,1-bis(hydroxymethyl)cyclopentane-3,4-diol (58). 3-Deoxycarba analogues 51 and 58 arose by migration of benzoyl group in the preparation of the dithiocarbonates.
通过碱催化加入甲醇、烯丙醇和乙硫醇到二甲基(4-氧代丁-2-烯-1-基)丙二酸酯(6)中,制备了外消旋二甲基4-甲氧基-(11和12)、二烯丙基4-烯丙氧基-(13和14)和二甲基4-(乙硫基)-2-羟基环戊烷-1,1-二羧酸酯(15和16)。去烯丙基化13和14得到4-羟基环戊烷27和28。用铝锂还原11-16得到相应的4-取代的2,2-双(羟甲基)环戊烷醇。从D-葡萄糖开始合成二甲基(2S,3S,4R)-、(2R,3S,4R)-3-苄氧基-4-甲酰氧基-2-羟基环戊烷-1,1-二羧酸酯(35,36)和二甲基(2S,3S,4R)-、(2R,3S,4R)-3-苄氧基-2-苯甲酰氧基-4-甲氧基环戊烷-1,1-二羧酸酯(39,40)。用铝锂还原二甲基环戊烷-1,1-二羧酸酯39和40,苯甲酰化形成羟基衍生物,苯甲基的氢解,将释放的羟基转化为二硫代碳酸酯,再用三丁基锡还原,去除保护基后得到(2R,4R)-1,1-双(羟甲基)-4-甲氧基环戊烷-2-醇((2R,4R)-17)和(3R,4R)-1,1-双(羟甲基)-4-甲氧基环戊烷-3-醇(51)。混合酯35和36还原后,主要产物为(2R,3R)-2-苄氧基-5-(羟甲基)己烷-1,3,6-三醇(52),次要产物为(2R,3S,4R)-3-苄氧基-1,1-双(羟甲基)-环戊烷-2,4-二醇(53)。后者被转化为(3R,4R)-1,1-双(羟甲基)-环戊烷-3,4-二醇(58)。在制备二硫代碳酸酯时,苯甲酰基的迁移导致3-去氧卡巴类似物51和58的形成。