Rapid Access to Substituted Piperazines via Ti(NMe2)(4)-Mediated C-C Bond-Making Reactions

CORC > 青海盐湖研究所 > 中国科学院青海盐湖研究所 > 青海盐湖研究所知识仓储

	Rapid Access to Substituted Piperazines via Ti(NMe2)(4)-Mediated C-C Bond-Making Reactions
	Chen, Zhou 2,3; Wu, Jian 2; Chen, Yanmei 2; Li, Lei 2; Xia, Yuanzhi 1; Li, Yahong 2; Liu, Wei 2; Lei, Tao 3; Yang, Lijuan 2; Gao, Dandan 3
刊名	ORGANOMETALLICS
	2012-09-10
卷号	31 期号:17 页码:6005-6013
文献子类	Article
英文摘要	An efficient Ti(NMe2)(4)-mediated C-C bond-forming methodology toward substituted piperazines, the basic skeleton of several biologically active natural products, has been developed. In reactions of tridentate monoanionic ligands bearing a [-HCNCH2-] linkage with Ti(NMe2)(4), unusual [3 + 3] dimerized complexes through C-C coupling of the putative titanium aza-allyl complex intermediate could be obtained. These complexes contain substituted piperazine backbones and could give rise efficiently to substituted piperazine derivatives via hydrolysis. Treatment of Ti(NMe2)(4) with a series of tridentate dianionic and bidentate monoanionic ligands bearing the [-HCNCH2-] moiety only generated chelated titanium complexes from ligand exchange reactions. Mechanistic studies using DFT/M06 calculations revealed that the methylene in the [-HCNCH2-] moiety of titanium complexes bearing tridentate monoanionic ligands could be deprotonated intramolecularly by dimethylamide anion with an activation energy of about 22 kcal/mol. The resulting titanium aza-allyl complexes from this beta-H abstraction step then undergo a consecutive stepwise [3 + 2] cycloaddition/ring expansion reaction facilely to form the dimerized complex. However, beta-H abstractions for Ti complexes bearing tridentate dianionic and bidentate monoanionic ligands were energetically demanding, as the negative charges could not be stabilized by the adjacent groups in the possible intermediates, explaining the experimental outcomes that no C-C coupled products were formed.
WOS关键词	EFFECTIVE CORE POTENTIALS ; COUPLING REACTIONS ; MOLECULAR CALCULATIONS ; TITANIUM COMPLEXES ; DENSITY FUNCTIONALS ; FORMING REACTIONS ; LIGANDS ; HYDROAMINATION ; POLYMERIZATION ; DERIVATIVES
WOS研究方向	Chemistry
语种	英语
WOS记录号	WOS:000308513000010
内容类型	期刊论文
源URL	[http://ir.isl.ac.cn/handle/363002/5639]
专题	青海盐湖研究所_青海盐湖研究所知识仓储青海盐湖研究所_盐湖资源综合利用工程技术中心中国科学院青海盐湖研究所
作者单位	1.Wenzhou Univ, Coll Chem & Mat Engn, Wenzhou 325035, Peoples R China 2.Soochow Univ, Coll Chem Chem Engn & Mat Sci, Key Lab Organ Synth Jiangsu Prov, Suzhou 215123, Peoples R China 3.Chinese Acad Sci, Qinghai Inst Salt Lakes, Key Lab Salt Lake Resources & Chem, Xining 810008, Peoples R China
推荐引用方式 GB/T 7714	Chen, Zhou,Wu, Jian,Chen, Yanmei,et al. Rapid Access to Substituted Piperazines via Ti(NMe2)(4)-Mediated C-C Bond-Making Reactions[J]. ORGANOMETALLICS,2012,31(17):6005-6013.
APA	Chen, Zhou.,Wu, Jian.,Chen, Yanmei.,Li, Lei.,Xia, Yuanzhi.,...&Li, Wu.(2012).Rapid Access to Substituted Piperazines via Ti(NMe2)(4)-Mediated C-C Bond-Making Reactions.ORGANOMETALLICS,31(17),6005-6013.
MLA	Chen, Zhou,et al."Rapid Access to Substituted Piperazines via Ti(NMe2)(4)-Mediated C-C Bond-Making Reactions".ORGANOMETALLICS 31.17(2012):6005-6013.