close

Вход

Забыли?

вход по аккаунту

?

код для вставки
2005
Azetidine derivatives
R 0045
Asymmetric Synthesis of 2-Mono- and 2,3-trans-Disubstituted Azetidines. —
(IX) and (XIII) are obtained with excellent diastereomeric and enantiomeric
07- 088 Azetidines
excesses in good overall yields. Key steps are a diastereoselective α-alkylation of
aldehyde SAMP-hydrazones with chloride (II), and a nucleophilic 1,2-addition of various organocerium reagents to the hydrazone C=N bond. An epimerization-free reductive removal of the auxiliary and subsequent N-tosylation affords N,O-protected 3-amino-1-alkanols (VI) and (XII). They are converted to the target azetidines by hydrogenolytic cleavage of the benzylic protecting group, followed by ring closure under
Mitsunobu conditions. Detosylation is easily achieved by sodium naphthalide. —
(ENDERS*, D.; GRIES, J.; KIM, Z.-S.; Eur. J. Org. Chem. 2004, 21, 4471-4482;
Inst. Org. Chem., RWTH Aachen, D-52074 Aachen, Germany; Eng.) — Klein
2005
Документ
Категория
Без категории
Просмотров
0
Размер файла
47 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа