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Reactions of Silicon Atoms with Conjugated π‐Systems: A Matrix‐Spectroscopic Study
Author(s) -
Maier Günther,
Reisenauer Hans Peter
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200390082
Subject(s) - chemistry , cyclopentadiene , adduct , conjugated system , stereospecificity , photochemistry , silicon , density functional theory , stereochemistry , computational chemistry , organic chemistry , catalysis , polymer
The reaction of silicon atoms with cyclopentadiene and butadiene in argon at 10 K has been studied. Addition to the conjugated π‐system of cyclopentadiene occurs in a [1,4]‐fashion. Upon irradiation the π‐adduct 3 rearranges to the formal insertion product 2 which has an unusual structure. Remarkably, a photoequilibrium between the two exo , endo isomers 2 and 4 can be observed. In the case of butadiene the addition is less stereospecific. The planar [1,4]‐adduct 11 is formed together with the [1,2]‐adduct 14 . Surprisingly, besides 11 a second, nonplanar [1,4]‐adduct 10 can be detected. The isomers 11 and 14 are transformed into 10 upon irradiation. The final photoproduct is silole 9 . The structural elucidation of the new species is based on isotopic labelling and a comparison of the experimental observations with the results from density functional calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)