The reaction of acetal-type protective groups in combination with TMSOTf and 2,2′-bipyridyl; mild and chemoselective deprotection and direct conversion to other protective groups
摘要:
A mild and chemoselective deprotection method of various acetal-type protective groups, such as MOM, MEM, BOM, and SEM ethers, has been developed. The combination of TMSOTf and 2,2'-bipyridyl was very effective for the deprotection, and the reaction proceeded via the formation of pyridinium intermediates, which were hydrolyzed to the corresponding alcohols in good to high yields. The features of this method are mild (almost neutral) reaction conditions and the tolerability of acid-sensitive functional groups. This method is also applicable for the direct conversion of MOM ether to BOM or SEM ether using the appropriate alcohols instead of H2O. (C) 2011 Elsevier Ltd. All rights reserved.
Remarkable effect of 2,2′-bipyridyl: mild and highly chemoselective deprotection of methoxymethyl (MOM) ethers in combination with TMSOTf (TESOTf)–2,2′-bipyridyl
developed for the synthesis of aliphatic fluorinated methyl ethers (ROCH2RF), specifically monofluoromethyl ethers (ROCH2F) and trifluoromethylthiomethyl ethers (ROCH2SCF3), through pyridinium-type salt intermediates derived from methoxymethyl (MOM) ethers. The addition of a fluorine source (F− or SCF3−) to the pyridinium-type salts afforded the corresponding fluorinated methyl ethers in good yields under
The reaction of acetal-type protective groups in combination with TMSOTf and 2,2′-bipyridyl; mild and chemoselective deprotection and direct conversion to other protective groups
A mild and chemoselective deprotection method of various acetal-type protective groups, such as MOM, MEM, BOM, and SEM ethers, has been developed. The combination of TMSOTf and 2,2'-bipyridyl was very effective for the deprotection, and the reaction proceeded via the formation of pyridinium intermediates, which were hydrolyzed to the corresponding alcohols in good to high yields. The features of this method are mild (almost neutral) reaction conditions and the tolerability of acid-sensitive functional groups. This method is also applicable for the direct conversion of MOM ether to BOM or SEM ether using the appropriate alcohols instead of H2O. (C) 2011 Elsevier Ltd. All rights reserved.
Remarkable effect of 2,2′-bipyridyl: mild and highly chemoselective deprotection of methoxymethyl (MOM) ethers in combination with TMSOTf (TESOTf)–2,2′-bipyridyl
The remarkable effect of 2,2â²-bipyridyl led to the successful development of the mild and highly chemoselective deprotection method of methoxymethyl (MOM) ethers using the combination of TMSOTf (or TESOTf) and 2,2â²-bipyridyl; this method can be applied to the direct conversion of the MOM group to other ethereal protective groups (e.g.benzyloxymethyl) with the corresponding alcohols.