报道了 Achmatowicz 衍生物的 Ru 催化异构化,该异构化开辟了使生物源呋喃平台多样化的未开发途径。通过计算和氘标记研究了这种正式的氧化还原中性分子内过程的机理见解。该转化被证明是一种强大的合成工具,可实现生物衍生单体和一系列 4-酮基-δ-戊内酯的合成,进一步促进了合成乙酰基合成的灵活策略的发展。还描述了两种天然产物(即 ( S , S )-muricatacin 和 ( S , S )-L-因子)的简洁且无保护基团的不对称全合成。
General Asymmetric Hydrogenation of Hetero-aromatic Ketones
摘要:
[GRAPHICS]trans-RuCL2[(R)-xylbinap][(R)-daipen] or the S,S complex acts as an efficient catalyst for asymmetric hydrogenation of hetero-aromatic ketones. The hydrogenation proceeds with a substrate-to-catalyst molar ratio of 1000-40000 to give chiral alcohols in high ee and high yield. The enantioselectivity appears to be little affected by the properties of the hetero-aromatic ring. This method allows for asymmetric synthesis of duloxetine, an inhibitor of serotonin and norepinephrine uptake carriers.
asymmetric reduction of prochiral ketones, with catecholborane as the hydride source. Enantioface differentiation is on the basis of the steric requirements of the ketone substituents. Aryl/ n-alkyl ketones are reduced in 90-93% ee and RC(O)Me (e.g. R = iPr, cycloC6H11, tBu) in 60-72% ee. Other borane sources and alternative catalyst structures based on indium do not form enantioselective catalysts
activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional‐group tolerance, and excellent enantioselectivities (85–98 % ee) in the hydrogenation of various ketones. These aspects are rare in earth‐abundant metal catalyzed hydrogenations. The utility of the protocol have been demonstrated in the asymmetric synthesis of a variety of key intermediates for chiral drugs
已经开发了一系列含有基于核苷的手性钳式配体的Mn I配合物,这些配合物具有模块化和可调的结构。该配合物在各种酮的氢化反应中显示出前所未有的高活性(高达9800 TON; TON =周转数),广泛的底物范围(81个实例),良好的官能团耐受性和出色的对映选择性(85-98%ee)。这些方面在稀土金属催化的氢化反应中很少见。该协议的实用性已在手性药物的多种关键中间体的不对称合成中得到证明。初步的机理研究表明,底物与催化剂相互作用的外层模式可能主导了催化作用。
Nucleophilic addition of dialkylzincs to aldehydes in hydrocarbon solvents is markedly accelerated by the presence of a catalytic amount of a β-dialkylamino alcohol. Use of certain sterically constrained chiral amino alcohols such as 3-exo-(dimethylamino)isoborneol or 1-t-butyl-2-piperidinoethanol effects highly enantioselective catalysis giving secondary alcohols in up to 99% ee. Dimethyl-, diethyl-
<i>De Novo</i> Asymmetric Synthesis of (+)-Monanchorin
作者:Yuzhi Ma、George A. O’Doherty
DOI:10.1021/acs.orglett.5b02651
日期:2015.11.6
A de novo asymmetric total synthesis of the guanidine alkaloid natural product (+)-monanchorin has been achieved in nine steps from the commodity chemicals furan and caproic acid. The asymmetry of the route was introduced by a Noyori reduction of an acylfuran. In addition, this route relies upon an Achmatowicz rearrangement, a diastereoselective palladium catalyzed glycosylation, reductive amination, and an acid catalyzed bicyclic guanidine mixed acetal formation.