"Front Matter". In: Organosilanes in Radical Chemistry - Index of

122 Unimolecular Reactions
t-Bu
t-Bu
Bu-t
Si SiMe2Ph t-Bu SiMe3 9
hν
t-Bu
t-Bu
Bu-t
Si
t-Bu SiMe 3
10
t-Bu
t-Bu
EtSH
Bu-t
H
Si SiMe3 Bu-t
t-Bu Bu-t
t-Bu
Si SiMe3 Bu-t
11
O 2
O
12 13
t-Bu O
t-Bu
Si O
Bu-t
SiMe3 Scheme 6.3 Proposed reaction mechanism for the formation of radical 11 and its fate
R
Si(H)Ph2 O
R
XS
SiPh2 O
R
XSH
SiPh2 O
R
5-endo
SiPh2 O
Scheme 6.4 Propagation steps for the intramolecular radical hydrosilylation of a carbon–
carbon double bond catalysed by thiol
Intramolecular hydrosilylation of the higher homologues 15 and 20 under
similar conditions gave also excellent yields of cyclized products [5]. The homoallyloxysilanes
15 afforded a mixture of six- and five-membered ring products in
a ratio of 4.5:1 for R ¼ Me and 2.5:1 for R ¼ Ph in favour of the larger ring
(Reaction 6.4). The EPR spectra obtained by the reaction of t-BuO: radical