BuLi-triggered phospha-Brook rearrangement: efficient synthesis of organophosphates from ketones and aldehydes
摘要:
A variety of organophosphates are synthesized from n-BuLi-triggered, (additional) solvent-free reactions of diethyl phosphite with both activated/unactivated ketones and aldehydes preferably at room temperature via phospha-Brook rearrangement. We could successfully synthesize the naphthylic/allylic phosphates using this approach. (C) 2015 Elsevier Ltd. All rights reserved.
Asymmetric Catalysis with Silicon-Based Cuprates: Enantio- and Regioselective Allylic Substitution of Linear Precursors
作者:Alexander Hensel、Martin Oestreich
DOI:10.1002/chem.201501371
日期:2015.6.15
linear allylic phosphates that makes use of catalytically generated cuprate‐type siliconnucleophiles is reported. The method relies on soft bis(triorganosilyl) zincs as silicon pronucleophiles that are prepared in situ from the corresponding hard lithium reagents by transmetalation with ZnCl2. With a preformed chiral N‐heterocyclic carbene–copper(I) complex as catalyst, exceedingly high enantiomeric excesses
Asymmetric Synthesis of α-Chiral Allylic Silanes by Enantioconvergent γ-Selective Copper(I)-Catalyzed Allylic Silylation
作者:Lukas B. Delvos、Devendra J. Vyas、Martin Oestreich
DOI:10.1002/anie.201300648
日期:2013.4.22
way: Regio‐ and enantioselective allylic substitution with a silicon nucleophile generated by copper(I)‐catalyzed SiB bond activation provides direct access to α‐chiral allylicsilanes from linear acceptors. The enantioconvergent catalysis employing McQuade's six‐membered N‐heterocyclic‐carbene–copper(I) catalyst is applicable to aryl‐ and alkyl‐substituted allylic phosphates (see scheme).
Highly Site- and Enantioselective Cu-Catalyzed Allylic Alkylation Reactions with Easily Accessible Vinylaluminum Reagents
作者:Yunmi Lee、Katsuhiro Akiyama、Dennis G. Gillingham、M. Kevin Brown、Amir H. Hoveyda
DOI:10.1021/ja0782192
日期:2008.1.1
An efficient method for catalytic asymmetric allylic alkylation (AAA) of allylic phosphates with vinylaluminum reagents is reported. The vinylmetal reagents are prepared by reaction of commercially available DIBAL-H and a terminal alkyne. The resulting vinylaluminum reagent can be used directy, without isolation or purification. AAA reactions are promoted in the presence of 0.5-2.5 mol % of a readily available chiral N-heterocyclic carbene (NHC) complex and 1-5 mol % commercially available and air stable Cu salt (CUCl2-2H(2)O). The desired products are typically obtained within 2-12 h in 74% to 95% isolated yield, 77% to >98% ee, and in >98% E selectivity: >98% S(N)2' selectively is obtained in all but one instance (90%). The hydroalummation/catalytic AAA sequence can be performed in a single vessel, on gram scale.
Nickel-Catalyzed C–H Coupling with Allyl Phosphates: A Site-Selective Synthetic Route to Linear Allylarenes
作者:Xuefeng Cong、Yuexuan Li、Yu Wei、Xiaoming Zeng
DOI:10.1021/ol501707z
日期:2014.8.1
reported that a nickel/phosphine catalyst allows the C–H allylation to occur effectively with the allyl site selectivity predominantly governed by steric effects. This reaction provides a facile and predictable route for the selective preparation of linear allylarenes from readily available benzamides and allyl phosphates.
A variety of organophosphates are synthesized from n-BuLi-triggered, (additional) solvent-free reactions of diethyl phosphite with both activated/unactivated ketones and aldehydes preferably at room temperature via phospha-Brook rearrangement. We could successfully synthesize the naphthylic/allylic phosphates using this approach. (C) 2015 Elsevier Ltd. All rights reserved.