Unexpected Highly Chemoselective Deprotection of the Acetals from Aldehydes and Not Ketones: TESOTf−2,6-Lutidine Combination
作者:Hiromichi Fujioka、Yoshinari Sawama、Nobutaka Murata、Takashi Okitsu、Ozora Kubo、Satoshi Matsuda、Yasuyuki Kita
DOI:10.1021/ja046103p
日期:2004.9.1
corresponding aldehydes. Of course, the compounds, which have both acetal and hydroxyl functions afforded the compounds obtained by the usual silylation of an alcohol and deprotection of an acetal without any problem. However, deprotection of the ketals from ketones was not observed during the conversion reaction of acetals from aldehydes. This chemoselectivity was confirmed in the reactions of the compounds
Reaction of the Acetals with TESOTf−Base Combination; Speculation of the Intermediates and Efficient Mixed Acetal Formation
作者:Hiromichi Fujioka、Takashi Okitsu、Yoshinari Sawama、Nobutaka Murata、Ruichuan Li、Yasuyuki Kita
DOI:10.1021/ja060328d
日期:2006.5.1
using various bases revealed the reaction and reached the best combination of TESOTf-base. It was very mild and highly chemoselective and proceeded under weakly basic conditions. Then, many functional groups such as allyl alcohol, silylether, acetate, methyl ether, triphenylmethyl (Tr) ether, 1,3-dithiolane, methyl ester, and tert-butyl ester could survive under these conditions. Furthermore, this methodology
Concise Asymmetric Total Synthesis of Scyphostatin, a Potent Inhibitor of Neutral Sphingomyelinase
作者:Hiromichi Fujioka、Yoshinari Sawama、Naoyuki Kotoku、Takuya Ohnaka、Takashi Okitsu、Nobutaka Murata、Ozora Kubo、Ruichuan Li、Yasuyuki Kita
DOI:10.1002/chem.200700871
日期:2007.12.17
achieved in a late stage of the total synthesis, and deprotection of the primary alcohol was conducted in the final step. During the synthesis several key reactions were attained: 1) intramolecularbromoetherification of the cyclohexadiene acetal; 2) stereoselective introduction of the tertiary alcohol, 3) deprotection of the acetal function to the aldehyde by combination with silyl triflate/2,4,6-collidine