XY–ZH systems as potential 1,3-dipoles. Part 1. Background and scope
作者:Ronald Grigg、H. Q. Nimal Gunaratne、James Kemp
DOI:10.1039/p19840000041
日期:——
XY–ZH Systems are considered in general terms and divided into four classes according to the number of constituent atoms that possess lone-pair electrons. Those systems in which the central Y atom possesses a lone pair are shown to be capable of participating in formal 1,2-H shifts generating 1,3-dipolar species. The scope of the reaction, including its possible relevance to the biochemistry of pyridoxal
X Y–ZH系统被视为通用术语,根据拥有孤对电子的组成原子的数量分为四类。中心Y原子具有孤对的那些系统显示出能够参与形成1,2-H移位的正式1,2-H移位,从而产生1,3-偶极物种。讨论了反应的范围,包括其可能与吡ido醛酶生物化学的相关性,并通过速率数据证明了一系列苯基甘氨酸和丙氨酸甲酯的芳基亚胺环加成N-苯基马来酰亚胺的速率对结构的影响。
Cycloadditions of arylidene imines of α-aminoacidesters to a range of dipolarophiles show substantial rate enhancements in the presence of Bronsted and Lewis acids. For Bronsted acids the rate is related to the pKa of the acid and cycloadditions to reactive dipolarophiles occur at room temperature. For the Lewis acids studied the rate acceleration decreases in the order Zn(OAc)2 > AgOAc > LiOAc >
XY–ZH Systems as potential 1,3-dipoles. Part 8. Pyrrolidines and Δ<sup>5</sup>-pyrrolines (3,7-diazabicyclo[3.3.0]octenes) from the reaction of imines of α-amino acids and their esters with cyclic dipolarophiles. Mechanism of racemisation of α-amino acids and their esters in the presence of aldehydes
Imines of α-aminoacidesters with aromatic, heterocyclic, and aliphatic aldehydes generate azomethine ylides stereospecifically by a prototropic shift on heating in toluene. The azomethine ylides undergo cycloaddition to N-phenylmaleimide, maleic anhydride, and p-naphthoquinone via an endo-transition state to give racemic, single diastereoisomeric, cycloadducts. α-Aminoacids undergo analogous cycloadditions
Brönsted and Lewis acid catalysis of XY–ZH cycloadditions
作者:R. Grigg、H. Q. N. Gunaratne
DOI:10.1039/c39820000384
日期:——
Cycloadditions of arylidene imdines of methyl phenylglycinate show substantial rate enhancement in the presence of Brönsted and Lewisacids; for Brönstedacids the rate is related to the pKa of the acid, whilst for the Lewisacids studied the rate acceleration decreased in the order Zn(OAc)2 > AgOAc > LiOAc > Mg(OAc)2.
在布朗斯台德和路易斯酸的存在下,苯基甘氨酸甲酯的亚芳基亚胺的环加成反应显示出显着的速率增加。对于布朗斯台德酸,速率与该酸的p K a有关,而对于路易斯酸,所研究的速率加速以Zn(OAc)2 > AgOAc> LiOAc> Mg(OAc)2的顺序降低。
Grigg, R., Bulletin des Societes Chimiques Belges, 1984, vol. 93, # 7, p. 593 - 604