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

60 Reducing Agents
S
Pr i
Ph
NH
(TMS) 3 SiH
AIBN, 80 �C
HN
Pr i
Ph
S Si(TMS) 3
92% (anti:syn = 84:16)
(4.21)
The removal of the tritylthio (Ph3CS) protecting group used in guanine
derivatives has been accomplished in a good yield by the action of
(TMS) 3SiH under free-radical conditions (Reaction 4.22) [49].
N
N
R
O
NH
N
(TMS) 3 SiH
AIBN, 115 �C N
R
(4.22)
H SCPh 3 NH 2
Secondary alkyl selenides are reduced by (TMS) 3SiH, as expected in view of
the affinity of silyl radicals for selenium-containing substrates (Table 4.3) [40].
Reaction (4.23) shows the phenylseleno group removal from the 2 0 position of
nucleoside [50]. Similarly to 1,3-dithiolanes and 1,3-dithianes, five- and sixmembered
cyclic selenoacetals can be monoreduced to the corresponding selenides
in the presence of (TMS) 3SiH [51]. The silicon hydride preferentially
approached from the less hindered equatorial position to give trans/cis ratios
of 30/70 and 25/75 for the five-membered (Reaction 4.24) and six-membered
cyclic selenoacetals, respectively.
t-Bu
RO
Se
RO
Se
O
O
N
SePh
NH
O
(TMS) 3 SiH
AIBN, 80 �C
N
O
81%
NH
(TMS) 3SiH AIBN, 80 �C
RO
O N
NH
O
t-Bu
Se
trans/cis = 30/70
RO
87%
O
SeSi(TMS) 3
(4.23)
(4.24)
Phenyl selenoesters have been reported to undergo reduction to the corresponding
aldehydes and/or alkanes in the presence of (TMS) 3SiH under free-