Hydrophosphination of Propargylic Alcohols and Amines with Phosphine Boranes
作者:Carl A. Busacca、Bo Qu、Elisa Farber、Nizar Haddad、Nicole Grět、Anjan K. Saha、Magnus C. Eriksson、Jiang-Ping Wu、Keith R. Fandrick、Steve Han、Nelu Grinberg、Shengli Ma、Heewon Lee、Zhibin Li、Michael Spinelli、Austin Gold、Guijun Wang、Peter Wipf、Chris H. Senanayake
DOI:10.1021/ol400309y
日期:2013.3.1
The first uncatalyzed hydrophosphinations of propargylic amines and alcohols with phosphine– borane complexes are described. The reactions proceed at ambient temperature or below without the use of protecting groups or the need to handle pyrophoric secondary phosphines, furnishing air-stable phosphineborane–amines and alcohols in good yields. Utilization of chiral propargylic substrates and unsymmetrical
Developing asymmetric iron and ruthenium-based cyclone complexes; complex factors influence the asymmetric induction in the transfer hydrogenation of ketones
作者:Jonathan P. Hopewell、José E. D. Martins、Tarn C. Johnson、Jamie Godfrey、Martin Wills
DOI:10.1039/c1ob06010d
日期:——
The preparation of a range of asymmetric iron and ruthenium-cyclone complexes, and their application to the asymmetric reduction of a ketone, are described. The enantioselectivity of ketone reduction is influenced by a single chiral centre in the catalyst, as well as by the planar chirality in the catalyst. This represents the first example of asymmetric ketone reduction using an iron cyclone catalyst.
Copper-catalysed cross-coupling of alkyl Grignard reagents and propargylic ammonium salts: stereospecific synthesis of allenes
作者:Manuel Guisán-Ceinos、Victor Martín-Heras、Rita Soler-Yanes、Diego J. Cárdenas、Mariola Tortosa
DOI:10.1039/c8cc03760d
日期:——
method to prepare enantiomerically enriched trisubstituted allenes using alkyl Grignardreagents and bench stable propargylic ammonium salts. Excellent yields as well as regio- and stereoselectivities are observed. Our conditions provide a solution to the allene racemization, which has been a long-standing problem when using Grignardreagents.
Utilization of whole cell mediated deracemization in a chemoenzymatic synthesis of enantiomerically enriched polycyclic chromeno[4,3-b] pyrrolidines
作者:Thangavelu Saravanan、Sushital Jana、Anju Chadha
DOI:10.1039/c4ob00615a
日期:——
Various aryl and alkyl substituted optically pure propargyl alcohols were obtained with excellent ee (up to >99%) and isolated yields (up to 87%) by deracemization using whole cells of Candida parapsilosis ATCC 7330. The whole cells show substrate specificity towards alkyl substituted propargyl alcohols and a switch in the enantioselectivity has been observed from ‘R’ to ‘S’ upon increasing the chain
通过使用副念珠菌ATCC 7330的全细胞进行消旋,获得了各种具有芳烃和烷基取代基的光学纯炔丙醇,具有优异的ee(最高> 99%)和分离的收率(最高87%)。整个细胞显示出对烷基取代的底物特异性随着链长的增加,已观察到炔丙醇和对映选择性的变化,从“ R ”变为“ S ”。对映体纯(R)-4-(3-羟基丁-1-炔基)苄腈,(R)-4-(联苯-4-基)丁-3-炔-2-醇,(S)- 3-羟基-5-苯基戊-4-酸乙酯和(S使用该策略获得了)-4-苯基丁-3-炔-1,2-二醇。如此获得的光学纯的炔丙醇用作手性起始原料,成功合成了对映体富集的多取代的吡咯烷和吡咯衍生物,成功地证明了化学酶促路线。
Synthesis of Enantiomerically Pure Allenes with Central and Axial Chirality Mediated by a Remote Sulfinyl Group
作者:José García Ruano、José Alemán、Vanesa Marcos
DOI:10.1055/s-0029-1217006
日期:2009.10
Enantiomerically pure 2-(p-tolylsulfinyl)benzylcopper reagents react with propargyl bromides and mesylates, affording enantiomerically pureallenes with central and axialchirality. Both regioselectivity (SN2′ processes) and configuration at the chiral axis are completely controlled by the sulfinylgroup. The stereoselectivity at the benzylic position is very high. Complete kinetic resolution and moderate
对映体纯的2-(对甲苯基亚磺酰基)苄基铜试剂与炔丙基溴和甲磺酸酯反应,得到具有中心和轴向手性的对映体纯的烯。区域选择性(S N 2'过程)和在手性轴上的构型均完全由亚硫酰基控制。在苄基位置的立体选择性非常高。可以实现外消旋炔丙基甲磺酸酯的完全动力学拆分和中等动态拆分。可以通过假设亚砜基氧使苄基铜稳定并作为分子内S N 2'亲核进攻的前一步,将三键与金属缔合来解释这种立体化学行为。 丙二烯-亚磺酰基-轴向手性-中心手性-不对称合成