Bismuth(III) Chloride Catalyzed Efficient and Selective Cleavage of Trityl Ethers

Abstract

A highly selective and efficient protocol has been developed for detritylation using 5 mol% BiCl 3 in acetonitrile. The cleavage proceeds at room temperature in high yields and the conditions are mild enough to tolerate a variety of acid-base sensitive functional groups.

Practical Conversion of Chlorosilanes into Alkoxysilanes without Generating HCl

“…[18] Both trityl and tert-butyl groups are known to form stable carbocations. Cleavage of the C À O bond with BiCl 3 alone was previously reported for trityl (-CPh 3 ) ethers.…”

Bismuth-Mediated Organic Reactions

“…In view of the versatile synthetic utility of b-hydroxy-1,3-dioxin-4-ones (for enantioselective versions of the reaction (for a review, see [121]) [150][151][152][153][154]; for other applications [155][156][157][158]), e.g. for the synthesis of 4-hydroxy-2-pyrones via the oxidation of the hydroxyl group [157], there was clearly a need for practical and efficient conditions that involve a bench-stable catalyst, used in very low loading.…”

“…In general, detritylation is accomplished under strong acidic conditions such as HCOOH, 80% CH 3 COOH, mineral acids, CF 3 COOH, or using Lewis acids such as ZnBr 2 , AlClEt 2 , Yb(OTf) 3 , and Ce(OTf) 4 . BiCl 3 -catalyzed trityl deprotection is a good alternative to these conventional methods as it avoids the use of protic acidic conditions [150]. BiCl 3 -catalyzed trityl deprotection is a good alternative to these conventional methods as it avoids the use of protic acidic conditions [150].…”

Concise Synthesis of 5-Methoxy-6-hydroxy-2-methylchromone-7-O- and 5-Hydroxy-2-methylchromone-7-O-rutinosides. Investigation of Their Cytotoxic Activities against Several Human Tumor Cell Lines

“…We found that the glycosidic bond of 7 was susceptible to cleavage even under mild acidic detritylation condition like using 1% I 2 in methanol at elevated temperature (60 °C). 9 Extensive experimentation disclosed that sabitha's recently developed protocol 10 using bismuth trichloride as a detritylation agent was the method of choice by which the desired product 8 could be obtained cleanly in 65% yield after 48 hours of stirring at room temperature in dry CH 3 CN, albeit with the recovery of some unreacted starting material (Scheme 1). …”