Palladium‐ and Rhodium‐Catalyzed Dynamic Kinetic Resolution of Racemic Internal Allenes Towards Chiral Pyrazoles
作者:Lukas J. Hilpert、Simon V. Sieger、Alexander M. Haydl、Bernhard Breit
DOI:10.1002/anie.201812984
日期:2019.3.11
resolution (DKR) of racemic allenes leading to N‐allylated pyrazoles is described. Such compounds are of enormous interest in medicinal chemistry as certified drugs and potential drug candidates. The new methods feature high chemo‐, regio‐ and enantioselectivities aside from displaying a broad substrate scope and functional group compatibility. A mechanistic rational accounting for allene racemization and trans‐alkene
A Facile and Efficient Method for Catalytic Acetylation of Alcohols with Acetic Acid
作者:Anindita Dewan、Utpal Bora、Dilip Kumar Kakati
DOI:10.5012/bkcs.2010.31.12.3870
日期:2010.12.20
however perchlorates are potentially explosive. Therefore, development of simple and environmentally friendly method for acetylation of alcohols utilizing inexpensive and readily available reagent is still desirable. Among the various transition metals, iron is one of the most abundant metals on the earth, and one of the most inexpensive and environmentally friendly ones. Therefore re- cently iron based
Asymmetric Synthesis of Allyl- and α-Allenylamines from Chiral Imines and Alkynes via (η<sup>2</sup>-Imine)Ti(O-<i>i</i>-Pr)<sub>2</sub> Complexes
作者:Kohki Fukuhara、Sentaro Okamoto、Fumie Sato
DOI:10.1021/ol034599u
日期:2003.6.1
[GRAPHICS]The reaction of a divalent titanium reagent Ti(O-1-Pr)(4)/2i-PrMgX with optically active arylaidimines derived from arylaidehydes and O-methylphenylglycinol provided, in a highly diastereoselective manner, chiral (eta(2)-imine)Ti(O-i-Pr)(2) complexes, which in turn reacted with 1-alkynes or propargyl compounds to give optically active allyl- and alpha-allenylamines, respectively.
Kinetic resolution of propargylic and allylic alcohols by Candida antarctica lipase (Novozyme 435)
作者:Cristiano Raminelli、João V. Comasseto、Leandro H. Andrade、André L.M. Porto
DOI:10.1016/j.tetasy.2004.08.022
日期:2004.10
A number of chiral propargylic and allylic alcohols were resolved by lipase-catalyzed kinetic resolution (Novozym 2 435). In some cases the enantiomeric excess was high (up to >99%). (C) 2004 Elsevier Ltd. All rights reserved.
Gold-Catalyzed Regioselective Hydration of Propargyl Acetates Assisted by a Neighboring Carbonyl Group: Access to α-Acyloxy Methyl Ketones and Synthesis of (±)-Actinopolymorphol B
作者:Nayan Ghosh、Sanatan Nayak、Akhila K. Sahoo
DOI:10.1021/jo101995g
日期:2011.1.21
suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-acyloxy methylketone is transformed to 1,2-diol