Coordination-Induced Stereocontrol over Carbocations: Asymmetric Reductive Deoxygenation of Racemic Tertiary Alcohols
作者:Mayuko Isomura、David A. Petrone、Erick M. Carreira
DOI:10.1021/jacs.9b00862
日期:2019.3.20
intermediate tertiary carbocations. This approach has been implemented to achieve the first example of enantioselective reductive deoxygenation of tertiaryalcohols. This reduction occurs with high enantio- (up to 96% ee) and regioselectivity (up to >50:1 rr) by applying a novel Hantzsch ester analogue as a convenient hydride source. In-depth mechanistic studies support the involvement of a tertiary carbocation
Transition‐Metal‐Free Radical Hydrotrifluoromethylation of Alkynes
作者:Kiran Matcha、Andrey P. Antonchick
DOI:10.1002/ejoc.201800291
日期:2019.1.23
A combination of readily available and bench‐stable CF3SO2Na and tBuOOH was efficiently used for hydrotrifluoromethylation of alkynes. An excellent trans‐selectivity was demonstrated in the synthesis of alkenes. The developed mild reaction conditions allow the supression of the competing Meyer–Schuster‐type rearrangement.
容易获得且稳定的CF 3 SO 2 Na和t BuOOH的组合有效地用于炔烃的加氢三氟甲基化。在烯烃的合成中表现出优异的反选择性。发达的温和反应条件可以抑制竞争性的Meyer–Schuster型重排。
Synthesis of Vinyl-, Allyl-, and 2-Boryl Allylboronates via a Highly Selective Copper-Catalyzed Borylation of Propargylic Alcohols
作者:Lujia Mao、Rüdiger Bertermann、Katharina Emmert、Kálmán J. Szabó、Todd B. Marder
DOI:10.1021/acs.orglett.7b03294
日期:2017.12.15
An efficient methodology for the synthesis of vinyl-, allyl-, and (E)-2-boryl allylboronates from propargylic alcohols via Cu-catalyzed borylation under mild conditions is reported. In the presence of commercially available Cu(OAc)2 or Cu(acac)2 and Xantphos, the reaction affords the desired products in up to 92% yield with a broad substrate scope (43 examples). Isolation of an allenyl boronate as
Brønsted acid mediated nitrogenation of propargylic alcohols: an efficient approach to alkenyl nitriles
作者:Xiaoqiang Huang、Ning Jiao
DOI:10.1039/c4ob00888j
日期:——
A novel and efficient approach to alkenyl nitriles from readily available propargylic alcohols has been developed. This nitrogenation reaction is transition-metal-free and could be conducted under air at ambient temperature, which makes this protocol promising and practical. Moreover, NH4Br is disclosed as an efficient additive to promote the stereoselectivity of this reaction.
demonstrated a very generalmethod for the preparation of essentially any terminal 2,3-allenol from the corresponding alkynols, which may be easily available from propargylic alcohols by alkylation, or from terminal alkynes by deprotonation and 1,2-addition with aldehydes or ketones, and subsequent base-catalyzed triple-bond migration. We have demonstrated a very generalmethod for the preparation of essentially