CP 2 TiCl 2 -catalyzed hydroalumination of internal alkynes: an access to ( Z )-olefins
摘要:
The reduction of alkynols with LiAlH4 in diglyme is a long known process leading to the formation of (E)-alkenols. We have, by serendipity, found that, in the presence of a catalytic amount (10%) of Cp2TiCl2. the stereoselectivity of the reaction is reversed, leading to the selective formation of the (Z)-alkenols. The scope and limitations of this methodology and a postulated catalytic cycle are also discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.
Abstract Allyl pyridyl ethers are important intermediates in organic synthesis, which could be accessed by Williamson or SNAr-type etherification. While Williamson etherification has been well studied, the SNAr-type reaction remains less explored. In this paper, a series of allyl pyridyl ethers were synthesized via transition metal-free SNAr-type etherification with different allylalcohols in good
A DYKAT die hard: A new class of chiral BiSO‐P ligands were effective for an unprecedented palladium‐catalyzed asymmetricallylicalkylation of indoles with the racemic title acetates through a dynamickineticasymmetrictransformation (DYKAT). The hydrogen bond formed between the sulfinyl group of the ligand and NH of indole plays an important role in the reaction.
a-UNSUBSTITUTED Y,d-UNSATURATED ALDEHYDES BY CLAISEN REARRANGEMENT: 3-PHENYL-4-PENTENAL
作者:Vogel, Dennis E.、Büchi, George H.
DOI:10.15227/orgsyn.066.0029
日期:——
An optimised and recoverable tartrate surrogate for sharpless asymmetric epoxidations
作者:David W. Knight、Ian R. Morgan
DOI:10.1016/j.tetlet.2008.10.069
日期:2009.1
The tetrahydroxy diester 7d (R = Pr-i) is almost as effective as diisopropyl tartrate in SAE reactions of (E)-allylic alcohols and can be recovered and re-used following a relatively simple work-LIP procedure. (C) 2008 Elsevier Ltd. All rights reserved.