Molecular Dynamics of dl- and meso-Bis(indenyl)dimethylsilane: Reexamination of the Mechanism of Interconversion by using Single Selective Inversion NMR

The molecular dynamics and cycloaddition chemistry of tris(1-indenyl)allylsilane Part 1Generation of the first crystallographically characterized tris(benzonorbornyl)silane

“…21 With the connectivity between the various H(1), H(2) and H(3) protons (within the Ðve-membered ring of each of the four individual indenyl ring environments) established, based on 1HÈ1H COSY spectral data, the set of indenyl proton resonances assignable to the homochiral RRR/SSS isomers and the three sets of H(1), H(2) and H(3) peaks attributable to the three indenyl environments in the RRS/SSR diastereomers were unequivocally assigned by careful scrutiny of the 1HÈ29Si shift correlated spectrum, a portion of which is presented as While indenes primarily undergo [2 ] 2] cycloadditions with tetracyanoethylene,34,35 (1-indenyl)silanes yield adducts apparently derived from [4 ] 2] cycloaddition processes involving the corresponding silyl-isoindene. Since the complex dynamic behaviour of tris(1-indenyl)allylsilane may be completely rationalized in terms of successive [1,5]-silicon shifts, we sought to intercept the transient isoindenes as they are sequentially generated, by in situ reaction with tetra- 1)wC (7) 1.903( 7) C( 1)wC( 7)wSi(1) 116.6(5) Si( 1)wC (27) 1.878( 7) C( 4)wC( 7)wSi(1) 120.6(5) Si( 1)wC (47) 1.908( 7) C( 24)wC( 27)wSi(1) 121.9(5) C(1)wC(2)…”

Diels-Alder Additions as Mechanistic Probes–Interception of Silyl-Isoindenes: Organometallic Derivatives of Polyphenylated Cycloheptatrienes and Related Seven-Membered Rings

“…In the mirror-symmetric meso isomer they are nonequivalent, whereas in the dl case the C 2 symmetry renders the methyls equivalent. Again, the intermediate isoindene was trapped as its Diels-Alder TCNE adduct [ 15 ].…”

Synthesis of Fused‐Ring Indenes by Ruthenium‐Catalyzed Ring‐Closing Metathesis

“…arrangements may occur after the silylation reaction by the [1,5]-silatropic shifts operating in silyl-substituted indenes. [36][37][38][39][40][41] Rigby and co-workers have investigated [1,5]silatropic shifts in disubstituted silylindenes and benzindenes showing that the initially formed, sterically crowded, 1,1-disubstituted product commonly undergoes a [1,5]-silatropic shift forming the less congested 1,3-disubstituted compound. [37] Thus, for compounds rac-20 and 21, the geminally substituted product 21 is likely to be formed first, which then, due to steric crowding, undergoes migration via isoindene to form the 1,3-substituted product (Scheme 7).…”