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. Author manuscript; available in PMC: 2021 Apr 6.
Published in final edited form as: Angew Chem Int Ed Engl. 2020 Feb 25;59(15):6115–6121. doi: 10.1002/anie.202000252

Table 1.

Optimization of Bicyclization Reaction Conditions

graphic file with name nihms-1554700-t0002.jpg
entry catalyst silane Y Solventb yield (%)c
1 C1 PhSiH3 3.0 Me2CO 40
2 C1 PhSiH3 0.5 Me2CO <5d
3 C1 Ph(i-PrO)SiH2 3.0 Me2CO 45
4 C1 TMDSO 3.0 Me2CO 42
5 C1 PhSiH3 3.0 i-PrOH 0
6 C1 TMDSO 2.0 PhCF3 0
7 C1 TMDSO 3.0 CH2Cl2 <5
8 C1 TMDSO 3.0 i-PrOH <5
9 C1 TMDSO 3.0 HFIP 87
10 C2 TMDSO 3.0 HFIP 31d
11 C3 TMDSO 3.0 HFIP <5
12 C1 TMDSO 0 HFIP <5d
13e C1 TMDSO O2 HFIP <5
14 – TMDSO 3.0 HFIP 0
graphic file with name nihms-1554700-t0003.jpg
a

All reactions were carried out using 5a (0.02 mmol), oxidant, catalyst (0.002 mmol), silane (0.07 mmol), in solvent (0.5 M) at ambient temperature (rt) for 4h under Ar.

b

Reaction mixtures were purged with Ar for 10 min. before the addition of silane.

c

For entries 1, 3, 4, 8, 9 isolated yields are reported, for other entries yields were estimated via 1H NMR spectroscopic analysis.

d

Incomplete conversion was observed.

e

Reaction was run for 12h. TBS: terti-butyldimethylsilyl; TMDSO: tetramethyldisiloxane; HFIP: 1,1,1,3,3,3-hexafluoroisopropanol