Thermal and Metal-Catalyzed Cyclization of 1-Substituted 3,5-Dien-1-ynes via a [1,7]-Hydrogen Shift: Development of a Tandem Aldol Condensation−Dehydration and Aromatization Catalysis between 3-En-1-yn-5-al Units and Cyclic Ketones
作者:Jian-Jou Lian、Chung-Chang Lin、Hsu-Kai Chang、Po-Chiang Chen、Rai-Shung Liu
DOI:10.1021/ja061203b
日期:2006.8.1
This work investigates the feasibility of thermal and catalytic cyclization of 6,6-disubstituted 3,5-dien-1-ynes via a 1,7-hydrogen shift. Our strategy began with an understanding of a structural correlation of 3,5-dien-1-ynes with their thermal cyclization efficiency. Thermal cyclization proceeded only with 3,5-dien-1-ynes bearing an electron-withdrawing C(1)-phenyl or C(6)-carbonyl substituent, but
这项工作研究了 6,6-二取代的 3,5-二烯-1-炔通过 1,7-氢转移进行热和催化环化的可行性。我们的策略始于了解 3,5-dien-1-ynes 与其热环化效率的结构相关性。热环化仅使用带有吸电子 C(1)-苯基或 C(6)-羰基取代基的 3,5-二烯-1-炔进行,但效率通常较低(产率为 20-40%)。基于这种构效关系,我们得出结论,这种 [1,7]-氢位移的特征在于“质子”氢位移,这应该由 pi-炔烃活化剂催化。我们制备了各种带有苯基或羰基的 6,6-二取代 3,5-二烯-1-炔,我们发现 RuCl(3)、PtCl(2)、和 TpRuPPh(3)(CH(3)CN)(2)PF(6) 催化剂来证实我们的假设:3,5-二烯-1-炔的 C(7)-H 酸度对于热环化至关重要。为了实现原子经济,我们使用弱酸性催化剂 CpRu(PPh(3))(2)Cl 开发了环烷酮和特殊 3-en-1-yn-5-als