Stereochemistry of Disilanylene-Containing Cyclic Compounds. Synthesis and Reactions of cis- and trans-3,4-Benzo-1,2-di(tert-butyl)-1,2-dimethyl-1,2- disilacyclobut-3-ene

Abstract

The reaction of cis- and trans-3,4-benzo-1,2-di(tert-butyl)-1,2-dimethyl-1,2-disilacyclobut-3-ene (1a and 1b) with chlorine gas in carbon tetrachloride proceeded stereospecifically to give meso- and rac-1,2-bis[(tert-butyl)chloromethylsilyl]benzene (2a and 2b, respectively). The condensation of 2a and 2b with lithium and sodium produced a mixture of cis- and trans-benzodisilacyclobutene 1a and 1b, respectively. The reaction of 1a and 1b with molecular oxygen proceeded with high stereospecificity to give the respective cis- and trans-4,5-benzo-2-oxa-1,3-disilacyclopent-4-ene. The palladium-catalyzed reactions of 1a and 1b with phenylacetylene, 1-hexyne, tert-butylacetylene, phenyl-1-propyne, and diphenylacetylene proceeded in a stereospecific fashion to give the corresponding 5,6-benzo-1,4-disilacyclohexa-2,5-diene derivatives. Similar reactions of 1a and 1b with trimethylsilylacetylene, dimethylphenylsilylacetylene, and mesitylacetylene gave stereospecifically the erythro- and threo-1,2-bis(silyl)benzene derivatives. The structure of trans-5,6-benzo-1,4-di(tert-butyl)-1,4-dimethyl-2-phenyl-1,4-disilacyclohexa-2,5-diene was determined by single-crystal X-ray crystallography.

Reactions of [o-(Fluorodimethylsilyl)phenyl]lithium with GeCl2 and SnCl2: Preparation of Polyfunctionalized Four-Membered and Five-Membered Cyclic Linkages of Heavier Group 14 Elements

“…To our knowledge, 2 and 3 are the first examples of benzocyclobutene and benzocyclopentene analogues incorporating two different heavier group 14 elements. 19,20 The fluorosilyl functionality on 2 and 3 is expected to open the door to new reaction modes of these cyclic linkages, and further investigations are in progress at our laboratory.…”

“…13 C chemical shifts were referenced to internal C 6 D 6 (δ=128.0) or external tetramethylsilane (δ = 0). 19 F chemical shifts were referenced to external CFCl 3 (δ = 0). 29 Si chemical shifts were referenced to external tetramethylsilane (δ = 0).…”

“…The 29 Si{ 1 H} NMR spectra showed that the endocyclic silicon atom resonates with coupling to R-and β-tin atoms at δ( 29 Si)=6.0 ( 1 J( 29 Si-117/119 Sn)=37 Hz, 2 J( 29 Si-117/119 Sn)= 6 Hz), while the two exocyclic silicon atoms resonate with coupling to fluorine atoms at δ( 29 Si)=20.0 (d, 1 J( 29 Si- 19 19 F coupling constant (75 Hz). 15b Intramolecular coordination of a fluorine atom to a tin atom also results in large 119 Sn- 19 F coupling constants in tin(IV) compounds bearing 2,4,-6-(CF 3 ) 3 C 6 H 2 or 2,6-(CF 3 ) 2 C 6 H 3 ligands (10- 19 Hz) 15c and in [2-(stannyl)ferrocenyl]fluoroborate (99-372 Hz).…”

“…15b Intramolecular coordination of a fluorine atom to a tin atom also results in large 119 Sn- 19 F coupling constants in tin(IV) compounds bearing 2,4,-6-(CF 3 ) 3 C 6 H 2 or 2,6-(CF 3 ) 2 C 6 H 3 ligands (10- 19 Hz) 15c and in [2-(stannyl)ferrocenyl]fluoroborate (99-372 Hz). 15d Thus, the observed large values in 3 can be ascribed to through-space coupling.…”

Photoinduced Rearrangement Reaction of 2-(Pentamethyldisilanyloxymethyl) phenylpentamethyldisilane

“…It is well known that disilane molecules having a siliconsilicon σ bond show unique properties in the photochemical [1][2][3][4] and thermal reactions 5 and in the transition metal catalyzed reactions [6][7][8][9][10][11][12][13][14] since the first reports on the unusual electronic spectra of aryldisilanes by Sakurai et al, 15 Gilman et al 16 and Hague et al 17 in 1964. In the context of our interest on the synthesis of silicon containing heterocyclic compounds by the photoreactions of ortho-substituted arylalkynyldisilanes [18][19][20][21][22][23][24][25][26][27][28][29] and aryldisilanes, 30,31 we have very recently reported on the photoreaction of (2-pentamethyldisilanyloxy)phenylpentamethyldisilane 32 in the presence of methanol or acetone affording a novel intramolecular photoproduct via silene intermediate.…”