[2 + 2]‐Cycloaddition eines Iminoborans an einen Methylen‐Titan‐Komplex

Abstract

[2 + 2]-Cycloaddition of an Iminoborane to a Methylene-Titanium Coordination CompoundThe iminoborane tBuB= NiBu (lc) reacts with the short-lived titanaethene H,C =TiCp2 (3) to give the l-aza-2-bora-4-titanacyclobutane 4c by [2 + 21-cycloaddition. A corresponding reaction with the more reactive iminoboranes 1 a, b, d is indicated by NMR data. CpaTi-CH2n,'

Synthesis and Characterization of Palladium and Platinum Iminoboryl Complexes

“…Cyclodimerization of iminoboranes within the coordination sphere of different transition metals was also reported, yielding η 4 ‐coordinated diazadiboretidines 1. 5a,c [2+2] Cycloadditions of different XBNR compounds with the short‐lived complex [Cp 2 TiCH 2 ] yielded 1‐aza‐2‐bora‐4‐titanacyclobutanes 5b. However, in contrast to the wealth of reported transition‐metal alkynyl complexes [L n MCCR],6 corresponding iminoboryl compounds [L n MBNR] are unknown.…”

Strain induced reactivity of cyclic iminoboranes: the (2 + 2) cycloaddition of a 1H-1,3,2-diazaborepine with ethene

“…16–23 Various iminoboranes have been investigated over the past decades to understand their reactivity 24–27 including the formation of BN-doped polycyclic aromatic hydrocarbons (PAHs), 28–32 formation of N-heterocyclic carbene coordinated iminoboranes, 25,33–36 synthesis of BN containing heterocycles, 37–44 (2 + 2) and (2 + 3) cycloaddition reactions with a number of polar double bonds ( e.g. , RR′CO) and dipolar reagents, 45–50 formation of iminoboryl carboranes, 19,51 and use of frustrated Lewis pairs to stabilize iminoboranes. 19,52–57 A series of ab initio computational studies performed by Gilbert compared iminoboranes and alkynes with respect to the electronic and geometric structure, as well as the reactivity in (2 + 2) and (2 + 4) cycloadditions towards alkenes and alkynes.…”

“…2,9,[13][14][15] Since then, iminoboranes have attracted tremendous attention. [16][17][18][19][20][21][22][23] Various iminoboranes have been investigated over the past decades to understand their reactivity [24][25][26][27] including the formation of BN-doped polycyclic aromatic hydrocarbons (PAHs), [28][29][30][31][32] formation of N-heterocyclic carbene coordinated iminoboranes, 25,[33][34][35][36] synthesis of BN containing heterocycles, [37][38][39][40][41][42][43][44] (2 + 2) and (2 + 3) cycloaddition reactions with a number of polar double bonds (e.g., RR ′ C]O) and dipolar reagents, [45][46][47][48][49][50] formation of iminoboryl carboranes, 19,51 and use of frustrated Lewis pairs to stabilize iminoboranes. 19,[52][53]…”

Reactions of 1,2-Azaborinine, a BN-Benzyne, with Organic π Systems

“…25 Cyclooligomerization was indeed also observed for dibenzo[c,e]- [1,2]azaborinine. 14,24 methylene-titanium 30 and neopentylidenetantalum complexes. 31 Paetzold et al also reported (2 + 3) cycloaddition reaction of iminoboranes with diazomethane.…”

“…Iminoboranes are isoelectronic with alkynes (see Scheme b), − but they are not kinetically inert due to a dipole moment and tend to form rings or polymers . Cyclooligomerization was indeed also observed for dibenzo­[ c , e ]­[1,2]­azaborinine. , Paetzold et al observed the (2 + 2) cycloaddition reaction of iminoborane with iminophosphanes in 1982, and later the (2 + 2) cycloaddition reaction with methylene-titanium and neopentylidenetantalum complexes . Paetzold et al also reported (2 + 3) cycloaddition reaction of iminoboranes with diazomethane .…”