We describe herein details of our efforts in developing a highly stereoselective synthesis of de novo chiral gamma-amino-ynamides through additions of lithiated ynamides to Ellman-Davis chiral N-tert-butanesulfinyl imines. While additions of ynamides could be highly stereoselective even without Lewis acids, the use of BF3-OEt2 completely reversed the stereoselectivity. On the other hand, additions of oxazolidinone-substituted, oxazinanone-substituted and tetrahydropyrimidinone-substituted ynamides behaved quite differently and functioned better with BF3-OEt2. The chirality of the oxazolidinone ring exerts no impact on the selectivity. This work also features a unique 5-endo-dig cyclization of oxazolidinone-substituted gamma-amino-ynamides that could be promoted with acid, leading to isothiazoles and 2,3-dihydro-isothiazole S-oxides.

中文翻译：

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使用锂化酰胺合成手性γ-氨基-酰胺。观察到具有中心倒置的独特 5-环化。


我们在此描述了我们通过将锂化的炔酰胺添加到埃尔曼-戴维斯手性N-叔丁亚磺酰亚胺中来开发从头手性γ-氨基-炔酰胺的高度立体选择性合成的努力的细节。虽然即使没有路易斯酸，添加炔酰胺也可以具有高度立体选择性，但 BF3-OEt2 的使用完全逆转了立体选择性。另一方面，恶唑烷酮取代、恶嗪酮取代和四氢嘧啶酮取代的炔酰胺的添加表现完全不同，并且与 BF3-OEt2 一起发挥更好的作用。恶唑烷酮环的手性对选择性没有影响。这项工作还具有恶唑烷酮取代的 γ-氨基-乙酰胺的独特 5-内位环化作用，可以用酸促进，产生异噻唑和 2,3-二氢异噻唑 S-氧化物。