Organocatalytic Asymmetric Synthesis of Propargylamines with Two Adjacent Stereocenters: Mannich-Type Reactions of In Situ Generated C-Alkynyl Imines with β-Keto Esters
作者:Taichi Kano、Taiga Yurino、Keiji Maruoka
DOI:10.1002/anie.201304963
日期:2013.10.25
Side by side: The title reaction is catalyzed by the chiral Brønsted acid (S)‐1, and affords hitherto less accessible chiral propargylamines, having twoadjacentstereocenters, in good to excellent diastereo‐ and enantioselectivities. Boc=tert‐butoxycarbonyl.
N-Boc-aminals as easily accessible precursors for less accessible N-Boc-imines: facile synthesis of optically active propargylamine derivatives using Mannich-type reactions
We developed a facile and practical synthesis of N-Boc-aminals, which can be used as precursors for less accessible N-Boc-imines. Aminals were obtained via simple dehydration condensation reactions of t-butyl carbamate (BocNH2) and various aldehydes in acetic anhydride, followed by filtration and washing with hexane. The obtained N-Boc-alkynylaminals could be successfully applied in enantioselective
asymmetric Mannichreaction of β-keto active methylene compounds with imines to afford chiral Mannich products, β-amino keto compounds, with continuous chiral centers, that are versatile synthetic intermediates for deriving various biologically active compounds. In particular, the thiourea fused γ-amino alcohols showed satisfactory catalytic activity in this reaction and afforded chiral Mannich products
在β-酮活性亚甲基化合物与亚胺的不对称曼尼希反应中检查了新型光学活性硫脲稠合γ-氨基醇的催化功能,以提供手性曼尼希产物,β-氨基酮化合物,具有连续手性中心,是通用的合成中间体用于衍生各种生物活性化合物。特别是,硫脲稠合的γ-氨基醇在此反应中表现出令人满意的催化活性,并以优异的化学产率(高达88%)和立体选择性(高达syn : anti /93 : 7 dr,高达99%)提供手性曼尼希产物。 ee)。