Hydrazides as Tunable Reagents for Alkene Hydroamination and Aminocarbonylation
摘要:
Benzoic hydrazides (R = Ph), which are remarkably bench and thermally stable reagents (often up to 230 degrees C), afford intramolecular hydroamination products upon heating at high temperatures (120-235 degrees C). A concerted Cope-type hydroamination event, followed by a hydrazide-mediated proton transfer step of the hydrazinium ylide intermediate, is proposed and supported by DFT calculations. In contrast, a simple modification of the reagent structure (R = Ot-Bu or NH2) favors the formation of aminocarbonylation products at 200 degrees C, and the tatter reaction is shown to be stereospecific.
Hydrazides as Tunable Reagents for Alkene Hydroamination and Aminocarbonylation
作者:Jean-Grégoire Roveda、Christian Clavette、Ashley D. Hunt、Serge I. Gorelsky、Christopher J. Whipp、André M. Beauchemin
DOI:10.1021/ja902558j
日期:2009.7.1
Benzoic hydrazides (R = Ph), which are remarkably bench and thermally stable reagents (often up to 230 degrees C), afford intramolecular hydroamination products upon heating at high temperatures (120-235 degrees C). A concerted Cope-type hydroamination event, followed by a hydrazide-mediated proton transfer step of the hydrazinium ylide intermediate, is proposed and supported by DFT calculations. In contrast, a simple modification of the reagent structure (R = Ot-Bu or NH2) favors the formation of aminocarbonylation products at 200 degrees C, and the tatter reaction is shown to be stereospecific.
Intramolecular Alkene Aminocarbonylation Using Concerted Cycloadditions of Amino-Isocyanates
作者:Ryan A. Ivanovich、Christian Clavette、Jean-François Vincent-Rocan、Jean-Grégoire Roveda、Serge I. Gorelsky、André M. Beauchemin
DOI:10.1002/chem.201600574
日期:2016.6.1
temperatures (150–200 °C), and issues included competing hydroamination and N‐isocyanate dimerization pathways. Herein, improved conditions for concerted intramolecular alkene aminocarbonylation with N‐isocyanates are reported. The use of βN‐benzyl carbazate precursors allows the effective minimization of N‐isocyanate dimerization. Diminished dimerization leads to higher yields of alkene aminocarbonylation