A transition-metal-free three-component process that combines aldehydes, 3-(tributylstannyl)propargyl acetates formed in situ from readily available propargyl acetates, and trialkylboranes provides access to a range of 1,2,4-trisubstituted homopropargylic alcohols. The addition of diisopropylamine plays a crucial role in the selective formation of homopropargylic alcohols. Importantly, this methodology
The trialkylborane/O2-mediated reaction of propargyl acetates having a tributylstannyl group at an alkyne terminus with aldehydes in a THF–H2O solvent system gave anti-δ,δ-disubstituted homoallylic alcohols with good to high diastereoselectivity. Intriguingly, two alkyl groups derived from trialkylborane were embedded into the reaction product. The trialkylborane plays a key role not only as a radical
由三烷基硼烷/ O 2介导的炔烃末端具有三丁基锡烷基的炔丙基乙酸酯与醛在THF-H 2 O溶剂体系中的反应可得到具有良好或高非对映选择性的抗-δ,δ-二取代均烯丙基醇。有趣的是,两个衍生自三烷基硼烷的烷基被嵌入反应产物中。三烷基硼烷不仅起自由基引发剂的作用,而且作为烷基自由基的来源也起着关键作用。
Olefination of Carbonyl Compounds through Reductive Coupling of Alkenylboronic Acids and Tosylhydrazones
作者:M. Carmen Pérez-Aguilar、Carlos Valdés
DOI:10.1002/anie.201200683
日期:2012.6.11
The partners decide: The CC bond‐forming reductive cross‐coupling of alkenylboronicacids and tosylhydrazones takes place under mild reaction conditions without the need of a metal catalyst, thus giving rise to olefination‐type products (see scheme). The position of the double bond in the product is determined by the structure of the coupling partners.
A new attachment/cleavage strategy: Polymer-bound allylic sulfones in a solid-phase route to trisubstituted olefins
作者:Chris Halm、Jerry Evarts、Mark J. Kurth
DOI:10.1016/s0040-4039(97)10062-4
日期:1997.11
By tethering allyl sulfone to polystyrene (3-steps from polystyrene beads consisting of lithiation, sulfination, and allylation), trisubstituted olefins can be generated by Cα-sulfone alkylation and subsequent resin cleavage by SN2′ nucleophilic displacement of sulfinate.
通过将烯丙基砜束缚在聚苯乙烯上(由聚苯乙烯珠子组成的3个步骤,由锂化,硫化和烯丙基化组成),可通过Cα-砜烷基化和随后通过亚磺酸盐的S N 2'亲核取代作用裂解树脂,生成三取代的烯烃。
ABE, KOJI;UEHARA, KATSUHIKO;TAKAHASHI, SENJI;MORI, NOBUO, CHEM. EXPRESS., 6,(1991) N, C. 189-191