Routes to putative N-acyl-D-ala-D-ala surrogates, beginning with the conversion of 4-, 5-, and 6-membered lactones into 5-, 6-, and 7-membered cyclic hydroxamates, are reported. The key step of the synthesis is trimethylaluminium-promoted cyclization of an ω-aminooxyester. The 7-membered cyclic hydroxamate crystallizes in a chair conformation. Extension of the reaction sequence to homoserine or homoserine lactone leads to cyclocanaline and N-acylated cyclocanalines. The 4-phenylacetamido derivative of cyclocanaline crystallizes in a boat conformation. The attachment of a 2-carboxypropyl substituent to the ring nitrogen of a 4-acylaminocyclocanaline has been effected, prior to cyclization, by coupling of the acyclic aminooxyester precursor to the triflate of benzyl lactate or, after cyclization, by coupling to tert-butyl α-bromopropionate in the presence of potassium fluoride alumina, followed by removal of the protecting group in each case. A six-membered homolog of the antibiotic lactivicin has been synthesized by the reaction of 4-phenylacetamidocyclocanaline with benzyl 2-oxoglutarate in the presence of carbodiimide, followed by hydrogenolysis. Starting with methyl 2,4-dibromo-2,4-dideoxy-L-erythronate, which is available in two steps from L-ascorbic acid, these reaction sequences have been applied to the stereospecific synthesis of a D-alanine derivative whose nitrogen atom is enclosed within a 3,4-disubstituted [1,2]oxazinan-3-one. Key words: D-ala-D-ala surrogate, cyclocanaline, homolactivicin, peptidoglycan, trimethylaluminium.
报道了将假定的N-酰-D-阿拉-D-阿拉替代物的合成途径,从将4、5和6元环内酯转化为5、6和7元环氢氧化物开始。合成的关键步骤是ω-氨氧酯的三甲基铝促进的环化反应。7元环氢氧化物以椅式构象结晶。将反应序列扩展到同型丝氨酸或同型丝氨酸内酯会导致环康纳林和N-酰化环康纳林的形成。环康纳林的4-苯乙酰氨基衍生物以船式构象结晶。在环康纳林的4-酰氨基环康纳林的环氮上附加2-羧基丙基取代基,可以通过将无环氨氧酯前体与苄乳酸三甲酯的三氟甲磺酸酯偶联,或在环化之后,通过与三氟甲基丙酸叔丁酯在氟化钾-氧化铝存在下偶联,然后在每种情况下去除保护基来实现。通过4-苯乙酰氨基环康纳林与苄基2-氧戊二酸酯在异亚胺存在下反应,然后进行氢解,合成了抗生素拉维西汀的六元同系物。从甲基2,4-二溴-2,4-二去氧-L-赤葡萄糖酸甲酯开始,该物质可以从抗坏血酸中经过两步合成,这些反应序列已被应用于立体特异性合成一种D-丙氨酸衍生物,其氮原子被包含在一个3,4-二取代[1,2]噁唑烷-3-酮内。关键词:D-ala-D-ala替代物,环康纳林,同型拉维西汀,肽聚糖,三甲基铝。