In this paper, the air-stable and readily available 1,3,5-triaza-7-phosphaadmantane (PTA) is reported as a practical and versatile nucleophilic phosphine organocatalyst. Under the mediation of 15–30 mol % of PTA, various electrophiles like aldehydes and imines readily undergo the Morita–Baylis–Hillman reactions with a variety of activated olefins, giving the corresponding adducts in high yields. In the phosphine-catalyzed [3+2] cycloaddition reaction of 4-substituted 2,3-butadienoates with N-tosylimines, PTA is also proven to be a comparable catalyst as tributylphosphine (PBu₃). By systematic comparison with other structurally similar N,P catalysts, it is concluded that the superiority of PTA in the above nucleophilic catalysis is attributable to its comparable nucleophilicity with that of trialkylphosphines. The feasibility to use PTA as an alternative catalyst in place of the air-sensitive trialkylphosphines is also discussed.

中文翻译：

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1,3,5-Triaza-7-phosphaadamantane（PTA）：一种实用，多功能的亲核膦膦有机催化剂。

在本文中，据报道，空气稳定且容易获得的1,3,5-triaza-7-phosphaadmantane（PTA）是一种实用且用途广泛的亲核膦有机催化剂。在15–30 mol％的PTA的介导下，各种亲电试剂（如醛和亚胺）容易与各种活化的烯烃发生Morita-Baylis-Hillman反应，从而以高收率得到相应的加合物。在4-取代的2,3-丁二烯酸酯与N-甲苯胺的膦催化的[3 + 2]环加成反应中，PTA也被证明是与三丁基膦类似的催化剂（PBu ₃）。通过与其他结构相似的N，P催化剂的系统比较，得出的结论是PTA在上述亲核催化中的优越性归因于其与三烷基膦可比的亲核性。还讨论了使用PTA替代对空气敏感的三烷基膦的替代催化剂的可行性。