Studies with trialkylsilyltriflates: new syntheses and applications

Amines vs. N‐Oxides as Organocatalysts for Acylation, Sulfonylation and Silylation of Alcohols: 1‐Methylimidazole N‐Oxide as an Efficient Catalyst for Silylation of Tertiary Alcohols

“…The reaction mixture was then heated to 40 °C for 8 h before the addition of MeOH (1 mL) to quench the reaction. The resulting solution was conc.…”

Synthesis and Some Properties of 4'-Phenyl-5'-Norcarbocyclic Adenosine Phosphonic Acid Analogues

“…The combined organic layer was washed with brine, dried over MgSO 4 , filtered, and concentrated. The residue was purified by silica gel column chromatography (EtOAc/hexane, 1:5) to give 10 (1.44 g, 73%) as a colorless syrup: (±)-Benzoic Acid 3-(t-Butyldimethylsilanyloxy)-3-phenylpent-4-enyl Ester (11). To a solution of 10 (1.6 g, 5.66 mmol) in anhydrous CH 2 Cl 2 (12 mL) was added 2,6-lutidine (2.42 g, 22.6 mmol) at 0 ºC.…”

“…Silylation of the tertiary hydroxyl group of 10 was successfully accomplished using t- butyldimethylsilyl trifluoromethanesulfonate (TBDMSOTf, 2,6-lutidine) 11 to give the fully protected compound 11. Removal of the benzoyl protecting group of 11 under methanolic ammonium condition (NH 3 /MeOH) provided the primary alcohol 12, which was oxidized to the aldehyde 13 using Swern oxidation conditions (Oxalyl chloride, DMSO, TEA).…”

Role of Hydroxymethyl Group as a New Hydrophilic 4'-Pocket in 5'-Norcarbocyclic Nucleoside Analogues

“…11 The secondary hydroxyl group of (8) was oxidized to the ketone (9) using Corey and Kim's oxidation conditions (NCS, DMS). 12 The corresponding ketone functional group of (9) was subjected to an addition re- action by vinylmagnesium bromide to give the tertiary hydroxyl analogue (10), which was again silylated (TBDMSOTf, 2.6-lutidine) 13 to give the protected compound (11). Removal of the benzyl protecting group of (11) under dissolving metal reduction 14 for a prolonged time (ca 25 min) furnished the desired alcohol (12), which was oxidized to the aldehyde (13) using Swern oxidation conditions 15 (DMSO, oxalyl chloride, TEA).…”

“…Removal of the benzyl protecting group of (11) under dissolving metal reduction 14 for a prolonged time (ca 25 min) furnished the desired alcohol (12), which was oxidized to the aldehyde (13) using Swern oxidation conditions 15 (DMSO, oxalyl chloride, TEA). The aldehyde (13) was again subjected to nucleophilic Grignard conditions 16 by vinylmagnesium bromide to yield divinyl (14), which was subjected to ring-closing metathesis (RCM) conditions using 2nd generation Grubbs catalyst (C46H65Cl2N2PRu) 17 to provide cyclopentenol (15a) (35%) and (15b) (36%), which were readily separated by silica gel column chromatography. The nuclear Overhauser enhancement (NOE) experiments with cyclopentenols (15a) and (15b) confirmed these assignments.…”