Chemistry of organosilicon compounds. 98. Photochemical generation of silacyclopropene

Abstract

Isolation of the first silacyclopropene, 1,1 -dimethyl-2,3diphenyl-1 -silacycloprop-2-ene, from the addition of the dimethylsilylene to diphenylacetylene was claimed by Volpin and co-workers in 1 962,2 although the product was demonstrated to be the dimer later.3 Very recently, Conlin and G a~p a r~~ and Seyferth, Annarelli, and V i~k~~ have reported that the addition of dimethylsilylene to acetylene really resulted in the formation of silacyclopropene.SiMe, RC=CRMe,Si:In a recent paper,5 we demonstrated that photolysis of styrylpentamethyldisilane gave silacyclopropane which afforded I-trimethylsilyl-l-methoxydimethylsilyl-2-phenylethane upon methanolysis. hu PhCH=CHSiMe,SiMe, -+ y y PhCH-CHSiMe,, MeOH -PhCH,CHSiMe,

Synthesis and Characterization of Methoxy-bridged Bis(silylene)tungsten Complexes

“…Irradiation of a solution of (Cp Me4 )W(CO) 3 Me and HEt 2 SiSiMe 2 OMe produces a methoxy-bridged bis(silylene) tungsten complex 3 (Eq. 1).…”

“…The proposed mechanism for the photolysis of (Cp/)W(CO) 3 Me in presence HEt 2 SiSiMe 2 OMe is shown in Scheme-1.…”

“…Silylene complexes have been proposed as reactive intermediates in a number of organosilicon transformations [1][2][3][4][5][6][7], however electrophilic nature of silylene ligands implies difficulties on there straightforward synthesis and consequent study on their properties. Efforts to synthesize silylene complexes resulted donor-stabilized silylene [8][9][10][11][12][13][14], donor stabilized bis(silylene) [15][16][17][18][19] and extremely donor stabilized sily(silyline) complexes [20].…”

Palladium- and Nickel-Catalyzed Carbon−Carbon Bond Insertion Reactions with Alkylidenesilacyclopropanes

“…Reversible oxidative addition of alkylidenesilacyclopropane 3 provides palladasilacyclobutane 15 2,3,5,10,12. For terminal alkynes and allenes, migratory insertion into the palladium–silicon bond3,8,10,12,14,17,34-36 affords intermediate 16 .…”

Comparisons between the chemistry of phosphirenes and silirenes

“…In other cases, the insertion is catalysed by nickel or palladium salts (ref. 14,27,28). The postulated mechanism involves the insertion of a zerovalent metallic moiety into the three-membered ring (eq.…”