Reaction of alpha-peroxy lactones with C, N, P, and S nucleophiles: Adduct formation and nucleophile oxidation by nucleophilic attack at and biphilic insertion into the peroxide bond
Reaction of alpha-peroxy lactones with C, N, P, and S nucleophiles: Adduct formation and nucleophile oxidation by nucleophilic attack at and biphilic insertion into the peroxide bond
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DOI：
10.1021/jo962039l
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发表时间：
1997-03-21
影响因子：
3.6
通讯作者：
Blancafort, L
中科院分区：
文献类型：
--
作者：
Adam, W;Blancafort, L
α-过氧内酯1与各种碳、氮、磷和硫亲核试剂的反应，在S（N）2攻击过氧化物键的更亲电的烷氧基氧时，产生不同的加成和氧转移产物，以及催化的Grob型断裂。亲核试剂的性质决定了开链中间体I的命运。因此，质子亲核试剂如伯胺和仲胺以及硫醇在S（N）2步骤之后通过质子转移导致第二中间体I'，而非质子胺和硫化物以及重氮烷导致氧化产物或环加合物10-15。三价磷亲核试剂，如膦和亚磷酸盐和二异丙基次硫酸盐更喜欢两亲插入，如亲核性而不是这些试剂的空间需求控制其反应性的事实所证明的。不稳定的加合物经过各种转化成为最终的稳定产物。对于质子亲核试剂，胺加合物5和6对于分离是足够持久的，而通过硫醇加成形成的次磺酸酯被进一步氧化成亚磺酸酯7和8或与过量的硫醇反应成相应的二硫化物。对于非质子亲核试剂，偶极中间体I分解成丙酮和CO2，亲核试剂再生（Grob型断裂），如DABCO和吡啶N-氧化物所见，或者它们挤出α-内酯以提供氧转移产物。相应的酮、吡啶N-氧化物、亚砜和砜通过该路线从重氮烷、吡啶、硫化物和亚砜获得。此外，重氮烷烃中间体I也环化为环加合物10-12。通过低温NMR光谱法观察到的热不稳定的磷加合物13-15分解成α-内酯和磷氧化物。类似地，从次硫酸盐加合物获得亚硫酸二异丙酯。至于α-内酯（α-过氧内酯的还原产物）的命运，二甲基衍生物或者低聚成低聚酯2a或者被甲醇捕获为α-甲氧基酸4a，而螺金刚烷基α-内酯脱羰基成金刚烷酮。
The reactions of the alpha-peroxy lactones 1 with a variety of carbon, nitrogen, phosphorus, and sulfur nucleophiles yield, on S(N)2 attack at the more electrophilic alkoxy oxygen of the peroxide bond, diverse addition and oxygen transfer products, together with the catalytic Grob-type fragmentation. The nature of the nucleophile determines the fate of the open-chain intermediate I. Thus, protic nucleophiles such as primary and secondary amines and thiols lead to the second intermediate I' through proton shift subsequent to the S(N)2 step, while nonprotic amines and sulfides, as well as diazoalkanes, lead to oxidation products or to the cycloadducts 10-15. Trivalent phosphorus nucleophiles such as phosphines and phosphites and diisopropyl sulfoxylate prefer biphilic insertion, as documented by the fact that the nucleophilicity rather than the steric demand of these reagents controls their reactivity. The labile adducts undergo a variety of transformations to the final stable products. For protic nucleophiles, the amine adducts 5 and 6 are sufficiently persistent for isolation, whereas the sulfenic esters formed by thiol addition are further oxidized to the sulfinic esters 7 and 8 or react with excess thiol to the corresponding disulfides. For aprotic nucleophiles, the dipolar intermediates I decompose into acetone and CO2 with regeneration of the nucleophile (Grob-type fragmentation), as seen for DABCO and pyridine N-oxide, or they extrude the alpha-lactone to afford the oxygen transfer product. The corresponding ketones, pyridine N-oxide, sulfoxides, and sulfones are obtained by this route from diazoalkanes, pyridine, sulfides and sulfoxides. Additionally, the diazoalkane intermediates I also cyclize to the cycloadducts 10-12. The thermally labile phosphorus adducts 13-15, which were observed by low-temperature NMR spectroscopy, decompose to the alpha-lactone and the phosphorus oxides. Analogously, diisopropyl sulfite is obtained from the sulfoxylate adduct. As for the fate of the alpha-lactones (the reduction products of the alpha-peroxy lactones), the dimethyl derivative either oligomerizes to the oligoester 2a or is trapped by methanol as the alpha-methoxy acid 4a, while the spiroadamantyl alpha-lactone decarbonylates to adamantanone.