Efficient method for the deprotection of tert-butyldimethylsilyl ethers with TiCl4-Lewis base complexes: application to the synthesis of 1beta-methylcarbapenems.
Efficient method for the deprotection of tert-butyldimethylsilyl ethers with TiCl4-Lewis base complexes: application to the synthesis of 1beta-methylcarbapenems.
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DOI：
10.1021/jo0604484
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发表时间：
2006-06
期刊：
影响因子：
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通讯作者：
A. Iida;Hiroki Okazaki;T. Misaki;M. Sunagawa;A. Sasaki;Y. Tanabe
中科院分区：
文献类型：
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作者：
A. Iida;Hiroki Okazaki;T. Misaki;M. Sunagawa;A. Sasaki;Y. Tanabe
TiCl_4-刘易斯碱（AcOEt，CH_3 NO_2）络合物顺利地脱保护叔丁基二甲基硅烷基（TBDMS）醚。由于刘易斯碱的影响，这些络合物的反应速度似乎较低，但比单独使用TiCl 4的反应速度大得多。成功地进行了脂族和芳族TBDMS醚（1和5）之间、1与苄基、烯丙基、甲苯磺酰基、甲氧基苯基和氯乙酰基醚（13、14、15、16和17）之间以及TBDMS和TBDPS醚（18和19）之间的选择性脱甲硅烷基化。TBDMS-羟醛、偶姻和β-内酰胺类似物9-12的脱甲硅烷基化由于相邻羰基的邻位协助而顺利进行。该方法已成功地应用于1 β-甲基碳青霉烯类抗生素20 a '-f'的实际合成。
TiCl4-Lewis base (AcOEt, CH3NO2) complexes smoothly deprotected tert-butyldimethylsilyl (TBDMS) ethers. The reaction velocity with these complexes, which seemed less reactive due to the influence of Lewis bases, was considerably greater than that with TiCl4 alone. Selective desilylations between aliphatic and aromatic TBDMS ethers (1 and 5), between 1 and benzyl, allyl, tosyl, methoxyphenyl, and chloroacetyl ethers (13, 14, 15, 16, and 17), and between TBDMS and TBDPS ethers (18 and 19) were successfully performed. Desilylation of TBDMS-aldol, acyloin, and beta-lactam analogues 9-12 proceeded smoothly due to anchimeric assistance by the neighboring carbonyl groups. The present method was successfully applied to the practical synthesis of 1beta-methylcarbapenems 20a'-f'.