尾-Diketiminato Nickel Imides in Catalytic Nitrene Transfer to Isocyanides

详细信息    查看全文

• 作者：Stefan Wiese ; Mae Joanne B. Aguila ; Elzbieta Kogut ; Timothy H. Warren
• 刊名：Organometallics
• 出版年：2013
• 出版时间：April 22, 2013
• 年：2013
• 卷：32
• 期：8
• 页码：2300-2308
• 全文大小：462K
• 年卷期：v.32,no.8(April 22, 2013)
• ISSN：1520-6041

文摘

The 尾-diketiminato nickel(I) species [Meb>3b>NN]Ni(2-picoline) (<b>1b>) serves as an efficient catalyst for carbodiimide (RN鈺怌鈺怤R鈥? formation in the reactions of a range of organoazides Nb>3b>R with isocyanides R鈥睳C. [Meb>3b>NN]Ni(CNR)b>2b> (R = ^tBu, Ar (Ar = 2,6-Meb>2b>Cb>6b>Hb>3b>)) species provide carbodiimides RN鈺怌鈺怤Ar鈥?upon reaction with Ar鈥睳b>3b> (Ar鈥?= 3,5-Meb>2b>Cb>6b>Hb>3b>). Nitrene transfer takes place via the intermediacy of nickel imides. Reaction of [Meb>xb>NN]Ni(2-picoline) (x = 2 or 3) with Ar鈥睳b>3b> gives the new dinickel imides {[Meb>xb>NN]Ni}b>2b>(渭-NAr鈥? (<b>4b> (x = 3) and <b>5b> (x = 2)) as deep purple, diamagnetic substances. The X-ray structure of {[Meb>2b>NN]Ni}b>2b>(渭-NAr鈥? (<b>5b>) features short Ni鈥揘b>imideb> distances of 1.747(2) and 1.755(2) 脜 along with a short Ni鈥揘i distance of 2.7210(3) 脜. These dinickel imides <b>4b> and <b>5b> react stoichiometrically with ^tBuNC to provide the corresponding carbodiimides ^tBuN鈺怌鈺怤Ar鈥?in good yield. Azide transfer takes place upon reaction of <b>1b> with TMS-Nb>3b> to give the square planar nickel(II) azide [Meb>3b>NN]Ni(Nb>3b>)(2-picoline) (<b>7b>). Stoichiometric reaction of dinickel dicarbonyl {[Meb>3b>NN]Ni}b>2b>(渭-CO)b>2b> with organoazides such as Ar鈥睳b>3b> is sluggish, indicating that <b>1b> is not an efficient catalyst for nitrene transfer from organoazides to CO to form isocyanates RN鈺怌鈺怬.