Half-sandwich rare-earth metal tris(alkyl) ate complexes catalyzed phosphaguanylation reaction of phosphines with carbodiimides: an efficient synthesis of phosphaguanidines
作者:Wangyang Ma、Ling Xu、Wen-Xiong Zhang、Zhenfeng Xi
DOI:10.1039/c5nj01136a
日期:——
Half-sandwich Y/Li ate complex displays better catalytic activity for phosphaguanylation reaction of phosphines with carbodiimides than the neutral yttrium complexes.
1,2,3-Triazoles are a privileged class of heterocycles in medicinal and agrochemical science. Here, we describe the base-promoted [3+2] annulation of carbodiimides with diazoacetonitrile. This reaction protocol permits access to a variety of novel 5-amino-4-cyano-1,2,3-triazoles in a regiospecific manner. Further derivatization is exemplified by a skeletal rearrangement and an N-functionalization of
Regioselective Ring Expansion of 2,4-Diiminoazetidines via Cleavage of C–N and C(sp<sup>3</sup>)–H Bonds: Efficient Construction of 2,3-Dihydropyrimidinesulfonamides
作者:Yang Wang、Yue Chi、Wen-Xiong Zhang、Zhenfeng Xi
DOI:10.1021/ja211486f
日期:2012.2.15
A highly regioselective base-mediated ring expansion of 2,4-diiminoazetidines via cleavage of C-N and C(sp(3))-H bonds is achieved for the first time to afford efficiently 2,3-dihydropyrimidinesulfonamides. The mechanism of the ring expansion via tandem 4 pi electrocyclic ring-opening/1,5-H shift/6 pi electrocydic ring-closing is well confirmed by the trapping experiments of two key intermediates and deuterium labeling studies.