Efficient One-Pot Multifunctionalization of Alkynes en Route to α-Alkoxyketones, α-Thioketones, and α-Thio Thioketals by using an Umpolung Strategy
作者:Zhou Xu、Rongliang Zhai、Ting Liang、Liming Zhang
DOI:10.1002/chem.201703087
日期:2017.10.12
All topsy turvy: A new and broadly applicable method for the synthesis of unique α-oxygenated ketones, α-thio ketones and α-thio thioketals via umpolung reaction of nucleophiles-alcohols/thioalcohols and N-alkenoxypyridinium salts generated from alkynes in a one-pot manner is reported for the first time. The reaction is controllable and tunable with good substrates scope (46 examples) and excellent
Rearrangements of silyl- and stannyl-substituted diallyl ethers: competition between the allyl-vinyl ether rearrangement and the [2,3] Wittig sigmatropic rearrangement
作者:T.N. Mitchell、F. Gießelmann、K. Kwetkat
DOI:10.1016/0022-328x(94)05307-w
日期:1995.5
Diallyl ethers containing two trimethylstannyl moieties or one triorganostannyl and one trimetyylsilyl moiety attached to the olefinic carbon atoms of one allyl group can undergo either an allyl-vinyl etherrearrangement or a [2,3] Wittig sigmatropic rearrangement when treated with a strong non-nucleophilic base. While the use of lithium diisopropylamide favours the Wittigrearrangement, lithium diethylamide
Palladium-Catalyzed Cascade C−O Cleavage and C−H Alkenylation of Phosphinyl Allenes: An Expeditious Approach to 3-Alkenyl Benzo[<i>b</i>
]phosphole Oxides
作者:Teng Liu、Xue Sun、Lei Wu
DOI:10.1002/adsc.201800103
日期:2018.5.16
time. The palladium‐catalyzed intramolecular cyclization provides an unprecedented cascade C−O cleavage and direct C−H alkenylation toward novel 3‐alkenyl benzo[b]phosphole oxides, along with broad group tolerance and high regioselectivity. Control experiments and mechanisticstudies explain the sequential performance of C(sp3)‐OAr cleavage and P=O directed C(sp2)‐Hactivation.
首次建立了由氧化膦定向的次膦基烯丙二烯分子内环化反应。钯催化的分子内环化作用提供了前所未有的级联C-O裂解和将CH-H烯基化成新型3-烯基苯并[ b ]磷氧化物的方法,并具有宽基团耐受性和高区域选择性。对照实验和机理研究解释了C(sp 3)-OAr裂解和P = O定向C(sp 2)-H活化的顺序性能。
disclose here that N-alkenoxypyridinium salts, generated readily upon gold-catalyzed additions of protonated pyridine N-oxide to C-C triple bonds of unactivated terminal alkynes, display versatile enolate umpolung chemistry upon heating and react with tethered arene nucleophiles in an SN2' manner. In a synthetically efficient one-pot, two-step process, this chemistry enables expedient preparation of valuable
与烯醇化物对应物相比,烯醇化物 umpolung 反应性为构建普遍存在的羰基化合物提供了有价值且可能独特的替代方案。我们在此公开了 N-链烯氧基吡啶鎓盐,在金催化下将质子化吡啶 N-氧化物与未活化末端炔烃的 CC 三键加成后很容易生成,在加热时显示出多功能的烯醇化极性化学,并以 SN2' 方式与系链芳烃亲核试剂反应。在合成高效的一锅两步法中,这种化学反应能够方便地从易于获得的芳基取代的线性炔烃中方便地制备有价值的苯并稠合七元/八元环酮,包括 O-/N-杂环酮基材。反应收率可达87%。
PROCESS FOR PREPARATION OF ALKYNYL CARBOXYLIC ACIDS
申请人:COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH
公开号:US20150025269A1
公开(公告)日:2015-01-22
The invention provides a simple, efficient, environmental friendly catalytic system for the direct carboxylation reaction using CO
2
under mild condition. A single step heterogeneous catalytic process for preparation of alkynyl carboxylic acids of formula I is disclosed.