Ncube Adela, Park Sheldon B, Chong J Michael
Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry (GWC(2)), Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
J Org Chem. 2002 May 31;67(11):3625-36. doi: 10.1021/jo0161734.
Reaction of N-Boc-N-tert-butylthiomethyl-protected alpha-aminoorganostannanes with n-BuLi generates the corresponding alpha-aminoorganolithiums. Reactions of these organolithiums with aromatic aldehydes provides N-protected beta-amino alcohols with diastereoselectivities up to >99:1 anti/syn; with aliphatic aldehydes, diastereoselectivities were typically 1:1. Diastereoselectivities varied depending on the amount of aldehyde used. The N-protected beta-amino alcohols could be deprotected to primary amines by treatment with NaH to generate oxazolidinones followed by basic hydrolysis. Alternatively, treatment of the protected amino alcohols with acid furnished cyclic acetals that could be deprotected to primary amines with BF(3).OEt(2) and HS(CH(2))(3)SH. Transmetalation of enantiomerically enriched organostannanes with n-BuLi at -95 degrees C provided organolithiums that, although less configurationally stable than N-Boc-N-methyl-protected alpha-aminoorganolithiums, could be trapped with aldehydes with near-complete retention of configuration.
N-叔丁氧羰基-N-叔丁基硫甲基保护的α-氨基有机锡烷与正丁基锂反应生成相应的α-氨基有机锂化合物。这些有机锂化合物与芳香醛反应可得到非对映选择性高达>99:1反式/顺式的N-保护β-氨基醇；与脂肪醛反应时，非对映选择性通常为1:1。非对映选择性随所用醛的量而变化。N-保护的β-氨基醇可用氢化钠处理生成恶唑烷酮，然后进行碱性水解，脱保护得到伯胺。或者，用酸处理保护的氨基醇可得到环状缩醛，再用三氟化硼乙醚和3-巯基-1-丙醇脱保护得到伯胺。对映体富集的有机锡烷在-95℃下与正丁基锂进行金属转移反应得到有机锂化合物，虽然其构型稳定性不如N-叔丁氧羰基-N-甲基保护的α-氨基有机锂化合物，但与醛反应时构型几乎完全保留。
