A Highly Efficient and UsefulSynthetic Protocol for the Cleavage oftert-Butyldimethylsilyl(TBS) Ethers Using a Catalytic Amount of Acetyl Chloridein Dry Methanol

Abstract

A wide variety of tert-butyldimethylsilyl (TBS) ethers as well as tert-butyldiphenylsilyl (TBDPS) ethers 1 can be easily deprotected to the corresponding parent hydroxyl compounds 2 by employing catalytic amounts of acetyl chloride in dry MeOH at 0°C to room temperature in good yields. Some of the major advantages are mild conditions, high efficiency, high selectivity, high yields, easy operation, and also compatibility with other protecting groups. Furthermore, no acetylation nor chlorination takes place under the experimental conditions. 0-5 °C, r.t. AcCl / dry MeOH R 1 = aryl / alkyl / sugar residue / nucleoside R 2 = H / alkyl; P = TBS / TBDPS Downloaded by: Karolinska Institutet. Copyrighted material. LETTER The Cleavage of tert-Butyldimethylsilyl (TBS) 695 Synlett 2003, No. 5, 694-698 ISSN 0936-5214 © Thieme Stuttgart · New York

Enantioselective Total Syntheses of (−)‐Rhazinilam, (−)‐Leucomidine B, and (+)‐Leuconodine F

“…The decarboxylative coupling of 13 with potassium carboxylate 12 afforded 18 in 52 %y ield in spite of the steric hindrance around the vinyl triflate unit. Treatment of am ethanol solution of 18 with ac atalytic amount of in situ generated hydrochloric acid [14] afforded alcohol 19,w hich was transformed into azide 5 via the mesylate intermediate.…”

“…In conclusion, we developed an ovel divergent total synthesis of three natural products,namely (À)-rhazinilam (1, 12 steps,16.4 %overall yield), (À)-leucomidine B(2,12steps, 14.5 %o verall yield), and (+ +)-leuconodine F( 3,1 4s teps, 11.6 %overall yield) from readily available (AE)-allyl 1-ethyl-2-oxocyclopentane-1-carboxylate (14). Heteroannulation of tetrahydropyridine 9 with bromoacetaldehyde (10)and oxalyl chloride (11), respectively,was successfully developed for the construction of the functionalized bicycles,w hich were subsequently diverged to three skeletally different natural products.Ahomogeneous palladium catalyst was exploited for the first time to accomplish as ubstrate-directed highly diastereoselective hydrogenation of as terically unbiased double bond.…”

The Prediction of the Absolute Stereochemistry of Primary and Secondary 1,2‐Diols by 1H NMR Spectroscopy: Principles and Applications

“…[12] 4) Oxidation to the aldehyde with Dess-Martin reagent. [13] 5) Asymmetric reduction to the (1S)-deuterated derivative with (S)-BINOL and tributyltin deuteride.…”

“…The esters 16 and 17 were prepared by selective esterification of the primary hydroxyl groups with either acetic acid (16) or MPA (17) followed by the esterification of the secondary hydroxyl groups with either MPA (16) or acetic acid (17). Compound 23 was prepared by protection of the primary hydroxyl group with TBSCl [11] (18) followed by esterification of the secondary alcohol with MPA (19), a selective deprotection of the primary hydroxyl group [12] (20), and oxidation [13] to the aldehyde (21). Next, the aldehyde was reduced to a chiral deuterated primary alcohol [14] (22) followed by its esterification with MPA (23).…”

A Highly Efficient and Chemoselective Synthetic Protocol for Tetrahydropyranylation/Depyranylation of Alcohols and Phenols

“…As part of our research program to develop new synthetic methodologies, [14] we conceived that bromodimethylsulfonium bromide, which can generate HBr in the reaction medium on reaction with alcohol, might be a useful catalyst for tetrahydropyranylation and depyranylation of alcohols and phenols. The catalyst bromodimethylsulfonium bromide has been utilized so far for the transformation of alcohols to the corresponding bromides, [15] oxidation of sulfides to disulfides, [16] deprotection of dithioacetals, [17] and preparation of α-bromoenones.…”