Cyclization reactions in synthetic organic chemistry

这五个研究领域有一个共同点。 它们都旨在制造环状有机化合物。 环状分子在自然界中极为常见，并且具有有趣和有益的生物活性的绝大多数有机分子含有至少一个环状部分。 1. 第一个研究领域是基于Nazarov反应。这项工作将在很大程度上建立在我们过去四年的开创性研究基础上，我们在过去四年中确定了丙二烯基乙烯基酮是非常有用的环化底物，在同一操作中形成了额外的键。这项新工作最令人兴奋的方面将是纳扎罗夫中间体的分子内捕获以及这一过程在天然产物合成中的应用。 2. 我们已经在第二个领域，偕酰化，活跃多年，但我们提出了一个令人印象深刻的演示偕酰化的合成潜力，通过使用的过程，使所有的螺旋桨环。此外，我们正在扩大相当大的偕酰化的范围，以合成对映体富集/纯形式的6元杂环。 3. 我们已经开发出的程序进行Pauson-Khand环化与阻碍基板。 我们的研究结果将被用来合成一种复杂的二萜生物碱，一个家庭的生物活性化合物之一，但现在我们的重点将转移到一个不同类型的环化，一个几乎没有优先权，这仍然是要实现的。 4. 将开辟两个新的调查领域。已报道衍生自环状1，3-二硫杂-化合物的阳离子可环化。我们将研究该反应以建立合成范围并深入了解其机理。一些产物可以转化为手性环丙烷/环丙酮。5. 第二个新领域涉及一种高活性物质，环己炔。取代的环己炔的环化从未被探索过。当环化反应能够以可预测的区域和立体选择性进行时，该环化反应将具有很大的合成价值。所有这些研究将作为一个严格的培训基地，教育研究生谁将成为理想的候选人在工业界和学术界的职位。

The five areas of proposed research have a common thread. They are all aimed at making cyclic organic compounds. Cyclic molecules are extremely common in Nature, and the vast majority of organic molecules with interesting and beneficial biological activities contain at least one cyclic portion. 1. The first area of investigation is based on the Nazarov reaction. This work will build considerably on our groundbreaking research of the past four years in which we established that allenyl vinyl ketones are very useful substrates for cyclizations with additional bond formation in the same operation. The most exciting aspects of the new work will be the intramolecular trapping of Nazarov intermediates and the application of this process to the synthesis of natural products. 2. We have already been active in the second area, geminal acylation, for many years, but we are proposing an impressive demonstration of geminal acylation's synthetic potential by using the process for making all the rings of propellanes. Also, we are extending considerably geminal acylation's scope to the synthesis of 6-membered heterocycles in enantiomerically enriched/pure form. 3. We have developed procedures for effecting the Pauson-Khand cyclization with encumbered substrates. Our results will be exploited to synthesize a complex diterpene alkaloid, one of a family of biologically active compounds, but now our focus will shift to a different type of cyclization, one with little precedence, that is still to be achieved. 4. Two new areas of investigation will be opened. Cations derived from cyclic 1,3-dithia-compounds have been reported to cyclize. We will investigate this reaction to establish the synthetic scope and to gain insights into the mechanism. Some products may be transformed into chiral cyclopropanes/cyclopropanones. 5. The second new area involves a highly reactive species, cyclohexyne. Cyclizations of substituted cyclohexynes have never been explored. This cyclization will have great synthetic value when the reaction can be carried out with predictable regio- and stereoselectivity. All this research will serve as a rigorous training ground to educate graduate students who will become ideal candidates for positions in industry and academia.