A ‘sting’ on Grubbs’ catalyst: an insight into hydride migration between boron and a transition metal

Abstract

An unusual ruthenium(ii) complex frozen at an intermediate point of hydride transfer between boron and ruthenium centres is reported.

Crystal field arguments to explain the trans labilisation within transition metal–borane complexes

“…Both Hill [10] and ourselves [20] have recently provided evidence for reversible hydride migration between boron and transition metal centres. This highlights the potential of the boron atom to act as a hydride store, opening up possibilities for new and interesting reactivity.…”

“…This has been shown in a large number of examples that have been reported over the past few years. The majority of compounds, which have been provided by Hill [2][3][4][5][6][7][8][9][10][11][12] and others [13][14][15][16][17][18][19][20][21], contain either the flexible scorpionate ligand, Tm [hydrotris(2-methyl-1-imidazolyl)borate] or similar derivatives (Fig. 2).…”

Strong agostic-type interactions in ruthenium benzylidene complexes containing 7-azaindole based scorpionate ligands

“…13 In this reaction a transfer of a hydride from boron occurred resulting in an unusual rearrangement and transfer of the former benzylidene fragment to the boron centre (Scheme 2). Isolation and characterisation of the resulting species 3 revealed a compound where the newly formed borohydride species was 'frozen' at an intermediate point of transfer between the boron and ruthenium centres.…”

“…10 During The School of Chemistry, University of Bristol,Cantock's Close,Bristol,UK,Fax: 44 (0)117 929 0509;Tel: 44 (0) these investigations, we have been interested in exploring transition metal-borane complexes as potential 'hydride stores' via aprocess involving transfer of hydride between metal and boron centres. 10b, 13 Such compounds could have a number of applications in catalysis and in hydrogen storage technologies.…”

Application of Ring-Closing Metathesis for the Synthesis of Benzo[3,4]azepino[1,2-b]isoquinolin-9-ones

“…12) Seven-membered heterocyclic rings are considered attractive molecules due to the points of structural determination of natural products as well as their interesting pharmacological actions. [3][4][5] In this paper we applied RCM [13][14][15][16][17][18][19][20][21][22][23][24][25][26] for the formation of seven-membered benzo [3,4]azepino [1,2-b]isoquinolinone 5, and the retrosynthetic pathway of benzo [3,4]azepino [1,2-b]isoquinolinone 5 is depicted in Chart 1. The coupling reaction of toluamide 7 with benzonitrile 8 afforded the 3-arylisoquinolinone 6, which could be modified to diene 4 as a key intermediate for the RCM reaction.…”