Effect of Water on Keck’s Catalytic Asymmetric Allylations of Aldehydes
作者:Michio Kurosu、Miguel Lorca
DOI:10.1055/s-2005-865202
日期:——
Ti(i-PrO) 4 , and unactivated or a large amount of activated 4 A MS in toluene is very effective in catalytic allylations of aldehydes using allyltributyltin. Allylations with 2.5 mol% of the catalyst provide homoallylic alcohols with greater than 95% ee. Very high syn-selective allylations of protected b-hydroxyaldehydes are achieved with 5 mol% of the BINOL/Ti(i-PrO) 4 complex.
由 BINOL、Ti(i-PrO) 4 和未活化或大量活化的 4 A MS 在甲苯中生成的络合物在使用烯丙基三丁基锡催化醛的烯丙基化中非常有效。使用 2.5 mol% 的催化剂进行烯丙基化可提供 ee 大于 95% 的高烯丙醇。使用 5 mol% 的 BINOL/Ti(i-PrO) 4 配合物可实现受保护的 b-羟基醛的非常高的顺式选择性烯丙基化。
Catalytic asymmetric allylations of achiral and chiral aldehydes via BINOL–Zr complex
作者:Michio Kurosu、Miguel Lorca
DOI:10.1016/s0040-4039(02)00139-9
日期:2002.3
The complex generated from BINOL, Zr(OtBu)4, and 4 Å MS in toluene–pivalonitrile is very effective for catalyticasymmetricallylation of aldehydes using allyltributyltin. The reactions of achiral aldehyde under these conditions are completed within 3 h using 10–20 mol% of the complex at −20°C. The ees of homoallylic alcohols can be enhanced up to 98% via the tandem asymmetric allylation–Oppenauer
由甲苯,新戊腈中的BINOL,Zr(O t Bu)4和4ÅMS生成的络合物对于使用烯丙基三丁基锡催化醛的催化不对称烯丙基化非常有效。在20°C下,使用10–20 mol%的配合物,可在3小时内完成这些条件下的非手性醛的反应。通过串联不对称烯丙基化-Oppenauer氧化可将均丙醇的ee提高至98%。对β-烷氧基醛的这些条件的范围和局限性进行了广泛的研究。
Scope and Limitations of the Scandium-Catalyzed Enantioselective Addition of Chiral Allylboronates to Aldehydes
作者:Dennis G. Hall、Michel Gravel、Hugo Lachance、Xiaosong Lu
DOI:10.1055/s-2004-822359
日期:——
Scandium triflate catalyzes the addition of camphor-derived allyl-, methallyl-, and crotylboronates to aldehydes to provide homoallylic alcohols with excellent diastereo- and enantioselectivity. Aromatic, aliphatic, and propargylic aldehydes can be used successfully in this system. Additional advantages of the camphor-diol allylboronates are their ease of synthesis, their availability in both enantiomeric forms, and their stability towards silica gel chromatography. The usefulness of this methodology is further demonstrated by the gram-scale synthesis of various homoallylic alcohols of high enantiomeric excess and by the concise synthesis of the pheromone (4S)-2-methyloctan-4-ol.
Catalytic Enantioselective and Catalyst-Controlled Diastereofacial-Selective Additions of Allyl- and Crotylboronates to Aldehydes Using Chiral Brønsted Acids
作者:Vivek Rauniyar、Dennis G. Hall
DOI:10.1002/anie.200504432
日期:2006.4.3
Total syntheses of (R)-argentilactone and (R)-goniothalamin via catalytic enantioselective allylation of aldehydes
作者:Ângelo de Fátima、Ronaldo Aloise Pilli
DOI:10.1016/j.tetlet.2003.09.122
日期:2003.11
The totalsyntheses of (R)-argentilactone (five steps, 25% overall yield) and (R)-goniothalamin (three steps, 61% overall yield) have been described through the enantioselectivecatalytic allylation of aldehydes (including a propargylic aldehyde) which provided a rapid access to these natural products that display very interesting biological activities.