Highly stereoselective [3 + 2] annulations by cyclopropanation of vinyl ethers with rhodium(II)-stabilized vinylcarbenoids followed by a formally forbidden 1,3-sigmatropic rearrangement
摘要:
A highly stereoselective 3 + 2 annulation has been developed by cyclopropanation of vinyl ethers with rhodium(II)-stabilized vinylcarbenoids to generate vinylcyclopropanes followed by a Et2AlCl-catalyzed 1,3-sigmatropic rearrangement. The success of this methodology rests on the remarkably stereoselectivity that is exhibited in both the cyclopropanation step and also the Et2AlCl-catalyzed vinylcyclopropane rearrangement.
A gold catalyzed formal intermolecular [2+3] cyclo-coupling of 1,3-enynes with phenols was developed to prepare dihydrobenzofuran derivatives with the addition of 2,6-dichloropyridine N-oxide, in which, a highly ortho-selective phenol SEAr functionalization was achieved by using 1,3-enynes as α-oxo vinyl gold carbenoid surrogates.
开发了金催化的 1,3-烯炔与苯酚的正式分子间 [2+3] 环偶联,通过添加 2,6-二氯吡啶N-氧化物制备二氢苯并呋喃衍生物,其中,高度邻位选择性的苯酚 S E Ar 官能化是通过使用 1,3-烯炔作为 α-氧代乙烯基金卡宾酸替代物来实现的。
Tandem Asymmetric Cyclopropanation/Cope Rearrangement. A Highly Diastereoselective and Enantioselective Method for the Construction of 1,4-Cycloheptadienes
作者:Huw M. L. Davies、Douglas G. Stafford、Brian D. Doan、Jeffrey H. Houser
DOI:10.1021/ja974201n
日期:1998.4.1
rhodium(II) (N-dodecylbenzenesulfonyl)prolinate (Rh2(S-DOSP)4, 1) in the presence of dienes results in a direct and highly enantioselective method for the formation of cis-divinylcyclopropanes. Combination of this process with a subsequent Cope rearrangement results in a highly enantioselective synthesis of a variety of cycloheptadienes containing multiple stereogenic centers.
在二烯存在下,通过铑 (II) (N-十二烷基苯磺酰基) 脯氨酸 (Rh2(S-DOSP)4, 1) 分解乙烯基重氮乙酸酯,可以直接且高度对映选择性地形成顺式二乙烯基环丙烷。该过程与随后的 Cope 重排相结合,导致多种含有多个立体中心的环庚二烯的高度对映选择性合成。
[1+1+3] Annulation of Diazoenals and Vinyl Azides: Direct Synthesis of Functionalized 1‐Pyrrolines through Olefination
作者:Vinaykumar Kanchupalli、Sreenivas Katukojvala
DOI:10.1002/anie.201801976
日期:2018.5.4
A dirhodium carboxylate catalyzed [1+1+3] annulation reaction of diazoenals and vinyl azides that gives synthetically important enal‐functionalized 1‐pyrroline derivatives was developed. The reaction involves a novel rhodium‐catalyzed olefination of diazoenals with vinyl azides via electrophilic enal carbenoids, resulting in a new class of enal acrylates. The annulation reaction was used for the direct
Convenient Synthesis of Vinyldiazomethanes from α-Diazo-β-Keto Esters and Related Systems
作者:Huw M. L. Davies、Paul W. Hougland、William R. Cantrell
DOI:10.1080/00397919208019285
日期:1992.4
Abstract A series of vinydiazomethanes were readily prepared by sodiumborohydridereduction of a-diazo-p-ketoesters followed by phosphorusoxychloride induced dehydration of the resulting a-diazo-p-hydroxyesters.
Highly Stereoselective C–C Bond Formation by Rhodium-Catalyzed Tandem Ylide Formation/[2,3]-Sigmatropic Rearrangement between Donor/Acceptor Carbenoids and Chiral Allylic Alcohols
作者:Zhanjie Li、Brendan T. Parr、Huw M. L. Davies
DOI:10.1021/ja303023n
日期:2012.7.4
The tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor rhodium carbenoids and chiral allyl alcohols is a convergent C-Cbond forming process, which generates two vicinal stereogenic centers. Any of the four possible stereoisomers can be selectively synthesized by appropriate combination of the chiral catalyst Rh(2)(DOSP)(4) and the chiral alcohol.