Silveira-Dorta Gastón, Álvarez-Méndez Sergio J, Martín Víctor S, Padrón José M
Instituto Universitario de Bio-Orgánica "Antonio González" (IUBO-AG), Centro de Investigaciones Biomédicas de Canarias (CIBICAN), Universidad de La Laguna. C/ Astrofísico Francisco Sánchez 2, 38206, La Laguna, Spain.
Beilstein J Org Chem. 2016 May 12;12:957-62. doi: 10.3762/bjoc.12.94. eCollection 2016.
An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction-olefination process. The sequential reduction with DIBAL-H at -78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner-Wadsworth-Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives.
报道了一种改进的对映体纯烯丙基胺的合成方案。源自天然氨基酸的N-保护α-氨基酸酯被用于一锅串联还原-烯化反应过程。在-78°C下用二异丁基氢化铝（DIBAL-H）进行连续还原，随后原位添加有机磷试剂，得到相应的烯丙基胺，无需分离中间醛。这避免了醛不稳定的问题。该方法对维蒂希（Wittig）和霍纳-沃兹沃思-埃蒙斯（Horner-Wadsworth-Emmons）有机磷试剂都有良好的耐受性。与之前的一锅法相比，观察到了更好的Z-（非对映）立体选择性。该反应过程的（非对映）立体选择性既不受反应溶剂的影响，也不受所使用的二异丁基氢化铝（DIBAL-H）量的影响。如丝氨酸和苏氨酸衍生物所示，该方法与游离羟基的存在相容。
