Synthesis of Tetrasubstituted Olefins by Pd-Catalyzed Addition of Arylboronic Acids to Internal Alkynes
作者:Chengxiang Zhou、Richard C. Larock
DOI:10.1021/ol047759q
日期:2005.1.1
[Reaction: see text] Tetrasubstitutedolefins are readily prepared by the Pd-catalyzed cis addition of two aryl groups from an arylboronic acid to opposite ends of the triple bond of internalalkynes. The synthesis proceeds under very mild reaction conditions and tolerates a wide variety of functional groups, including alcohol, aldehyde, ester, TMS, and acetal groups.
Tetrasubstituted Olefin Synthesis via Pd-Catalyzed Addition of Arylboronic Acids to Internal Alkynes Using O<sub>2</sub> as an Oxidant
作者:Chengxiang Zhou、Richard C. Larock
DOI:10.1021/jo060104d
日期:2006.4.1
alkynes provides a convenient route to a wide variety of tetrasubstituted olefins. The reaction is conducted in DMSO using molecular O2 as an oxidant in the absence of any base. The reaction involves the cis addition of two aryl groups from the arylboronic acid to opposite ends of the triple bond of the internal alkyne. The synthesis tolerates a wide variety of functional groups, including alcohol, aldehyde
and dioxygen serve as oxidants in highly stereoselective oxidative Pd‐catalyzed Heck arylations in which aryl boronicacids are used to synthesize triarylalkyl‐substituted olefins. The reactions occur under very mild conditions at room temperature. As an example, the threefold sequential arylation of methyl acrylate is the crucial step in the stereoselective synthesis of Z‐Tamoxifen.
The insertion of lithiated epoxides into boronic esters followed by thermal syn-elimination provides a stereospecific entry to alkenes. This process avoids transition metals and is amenable to iteration to provide higher substitution patterns.
SnCl4–Zn: a novel reductive system for deoxygenative coupling of aliphatic, aromatic, chalcone epoxide, and indanone carbonyl compounds to olefins
作者:Gulab Khushalrao Pathe、Naseem Ahmed
DOI:10.1016/j.tetlet.2015.01.194
日期:2015.3
SnCl4–Zn complex provided a novel reductive system in the deoxygenative cross-coupling of aliphatic, aromatic, chalcone epoxide and indanone carbonyl compounds to olefins in high yield (55–86%) at reflux temperature in THF. The advantage of this reagent is inexpensive, short reaction time, and high yield compared to the reagents used in the McMurry cross-coupling reaction.