Reactivity and Structural Diversity in the Reaction of Guanidine 1,5,7-Triazabicyclo[4.4.0]dec-5-ene with CO₂, CS₂, and Other Heterocumulenes

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• 作者：Niklas von Wolff ; Claude Villiers ; Pierre Thué ; ry ; Guillaume Lefè ; vre ; Michel Ephritikhine and Thibault Cantat
• 刊名：European Journal of Organic Chemistry
• 出版年：2017
• 出版时间：January 18, 2017
• 年：2017
• 卷：2017
• 期：3
• 页码：676-686
• 全文大小：1809K
• ISSN：1099-0690

文摘

The guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) reacted with the heterocumulenes CO₂, CS₂, iPr₂NCNiPr₂, p-tolylNCO, and p-tolylNCS to give three types of products: TBD–CO₂ (1) and TBD–p-tolylNCS (5), resulting from the addition of the cumulene to TBD, TBD(–H)({iPrNH}–C=N{iPr}) (3) and TBD(–H)(p-tolylNHCO) (4), resulting from addition of the N–H bond of TBD to the C=N bond of the cumulene, and the dithiocarbamate salt [TBDH][TBD(–H)CS₂] (2) after transfer of a proton to a second molecule of TBD. Competition reactions indicated that the stability of the compounds decreases in the order 4 > 5 > 1 > 2 > 3. DFT calculations showed that the relative stabilities of the products are governed by both the Lewis acidity of the heterocumulene and the Brønsted basicity of the TBD(–H)–cumulene anion, whereas their distinct structures are determined by the latter, with the most basic site governing the geometry of the final product.