[3+2] Cycloaddition of Propargylic Alcohols and α‐Oxo Ketene Dithioacetals: Synthesis of Functionalized Cyclopentadienes and Further Application in a Diels–Alder Reaction

Fang, Zhongxue; Liu, Jianquan; Li, Qun; Bi, Xihe

doi:10.1002/ange.201403014

Cited by 7 publications

(2 citation statements)

References 82 publications

(36 reference statements)

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“…Instead of FeBr 3 , BF 3 ⋅OEt 2 could also catalyze this coupling process. The resulting gem ‐bis(alkylthio)‐substituted vinylallenes 24 with different functional groups have been usefully applied to synthesize δ‐lactams 25 , δ‐lactones 26 , indenes 27 , and cyclopentadienes 28 , respectively.…”

Section: α‐C−h Functionalizationmentioning

confidence: 99%

Recent Advances in Metal‐Catalyzed Bond‐Forming Reactions of Ketene S,S‐Acetals

Wang

Liu

2018

Adv Synth Catal

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Scheme 6. CuBr 2 /BF 3 ·OEt 2 -co-catalyzed [3+ +2] cyclizations of 1 and 8/10. Scheme7.CuBr 2 -catalyzed reaction of 1 and 13. Scheme8.CuBr 2 -catalyzed reaction of 1 and 15. Scheme 19. AlCl 3 -catalyzed multicomponentr eactionsb ased on a-benzoyl ketened imethyl thioacetal. Scheme20. FeCl 3 -catalyzed cross-coupling of 1 and 44. Scheme 30. Cu(OH) 2 -catalyzed a-trifluoromethylation of 1. Scheme 31. Cu(OH) 2 -catalyzed a-alkoxylationof1. Scheme 32. CuI-catalyzed a-thiomethylation of 1. Scheme33. CuCl-catalyzed a-azidation of 1. Scheme 43. Pd-catalyzedd esulfurative cross-coupling and cyclization of 71 and 90. Scheme 44. FeCl 3 -catalyzedd esulfurative indolizationo f74.

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Section: α‐C−h Functionalizationmentioning

confidence: 99%

Recent Advances in Metal‐Catalyzed Bond‐Forming Reactions of Ketene S,S‐Acetals

Wang

Liu

2018

Adv Synth Catal

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“…It provided an ew general access to functionalized 3 in one step under mild reaction conditions (30 8 8C), low substrate ratio (as low as equimolar), and low catalyst loading (1-4 mol %). It complements af ew shortcomings of the intramolecular approaches, [18] tailormade ynamides with Au vinyl carbenoids, [10,19] cycloaddition, [20] and approaches that use stoichiometric amounts of organometallic reagents. [21] High yield, functional-group compatibility,a nd regioselectivity (up to 46:1, > 20:1 in general) were noted in cases with either the commercially available or simple terminal alkynes 2 ( Table 2, Sets 1-3).…”

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confidence: 99%

[(NHC)Ni^IIH]‐Catalyzed Cross‐Hydroalkenylation of Cyclopropenes with Alkynes: Cyclopentadiene Synthesis by [(NHC)Ni^II]‐Assisted C−C Rearrangement

Huang

2019

Angewandte Chemie

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Ac ross-hydroalkenylation/rearrangement cascade (HARC), using ac yclopropene and alkyne as substrate pairs, was achieved for the first time by using new [(NHC)Ni-(allyl)]BAr F catalysts (NHC = N-heterocyclic carbenes). By controlling the (NHC)Ni II Hr elative insertion reactivity with cyclopropene and alkyne,abroad scope of cyclopentadienes was obtained with highly selectively.The structural features of the new (NHC)Ni II catalyst were important for the success of the reaction. The mild reaction conditions employed may serve as an entry for exploring (NHC)Ni II -assisted vinylcyclopropane rearrangement reactivity.Cyclopropenes (1)are important building blocks in organic synthesis,a nd significant advances for their synthesis have been made recently by using new transition-metal catalysts. Other than the use of traditional methods, [1] catalysts like Au, [2] Rh, [3] Cu, [4] Zn, [5] Pt, [6] and Pd [7] are particularly useful in ring-opening reactions of 1. [8] Thei ntermediates,s uch as the reactive vinyl metal carbenoids and the cyclopropane ions,are often trapped by either nearby functional groups on the skeleton or external nucleophiles (Scheme 1a), providing ag eneral route to substituted furans,p yrans,a nd acyclic products.T ransition-metal hydride catalysts or their equivalents [9] could potentially be one of the most ideal approaches for cyclopropene functionalization since it could insert into the olefin and allow subsequent insertions of various reaction partners.However, their use in selective transformation of 1 is rarely reported. [7] An umber of other possible reactivities of 1 with transition-metal hydride lead to unfavorable consumption of 1,and have severely limited the progress of the crossreaction development. With either too high of an insertion activity of 1 or competing pathways from other reaction partners,such as the alkyne 2,the non-selective oligomerization or homoreaction reactivity often dominates (Scheme 1bi).M oreover,o ther possible rearrangements were reported as one of the possible pathways for allylÀNu formation, and that made the hydride approach even more complicated (Scheme 1bii).A sac onsequence,h ighly selec-tive cross-transformations of 1 by transition-metal hydride catalyst and external p systems [2b,3d, 4, 10] remains elusive. Oxidative addition followed by either rearrangement or trapping is still dominating the field in Ni-catalyzed threemembered ring opening (Scheme 1c). [11,12] Herein, across-hydroalkenylation/rearrangement cascade (HARC) of 1 and 2 is achieved for the first time by using an ew set of [(NHC)Ni(allyl)]BAr F catalysts (Scheme 1d; NHC = N-heterocyclic carbene). Unlike the cross-hydroalkenylation of two different alkenes, [9b,13, 14] it provides highly efficient access to synthetically valuable,functionalized cyclopentadienes (3)r ather than gem-olefins.I nstead of using oxidative addition conditions for three-membered ring opening by Ni 0 in Scheme 1c,t he CÀCb ond cleavage is possibly assisted by (NHC)Ni II in as ubsequent rearrangement under mild cond...

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Tandem Chemoselective 1,2‐/1,4‐Migration of the Thio Group in Keto Thioesters: An Efficient Approach to Substituted Butenolides

et al. 2016

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We report herein an efficient and mechanistically unique tandem chemoselective 1,2-/1,4-migrationo ft he thio group in keto thioesters that provides substituted butenolides in moderate to excellent yields.T hus, a-keto thioesters in the presence of stabilized phosphonate carbanions undergo tandem 1,2-sulfur migration;w hereas1 ,4-migration of the thio group has been achieved with the same thioest-ers after the treatment with Wittig reagents followed by BF 3 ·OEt 2 -catalyzed tandem reaction. Thec rossover experiments and the isolation of intermediates reveal as tepwise mechanism for botho ft hese transformations.Scheme 1. Commonstrategies for the 1,2-/1,4-migration of the thio group.

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[3+2] Cycloaddition of Propargylic Alcohols and α‐Oxo Ketene Dithioacetals: Synthesis of Functionalized Cyclopentadienes and Further Application in a Diels–Alder Reaction

Cited by 7 publications

References 82 publications

Recent Advances in Metal‐Catalyzed Bond‐Forming Reactions of Ketene S,S‐Acetals

Recent Advances in Metal‐Catalyzed Bond‐Forming Reactions of Ketene S,S‐Acetals

[(NHC)Ni^IIH]‐Catalyzed Cross‐Hydroalkenylation of Cyclopropenes with Alkynes: Cyclopentadiene Synthesis by [(NHC)Ni^II]‐Assisted C−C Rearrangement

Tandem Chemoselective 1,2‐/1,4‐Migration of the Thio Group in Keto Thioesters: An Efficient Approach to Substituted Butenolides

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[3+2] Cycloaddition of Propargylic Alcohols and α‐Oxo Ketene Dithioacetals: Synthesis of Functionalized Cyclopentadienes and Further Application in a Diels–Alder Reaction

Cited by 7 publications

References 82 publications

Recent Advances in Metal‐Catalyzed Bond‐Forming Reactions of Ketene S,S‐Acetals

Recent Advances in Metal‐Catalyzed Bond‐Forming Reactions of Ketene S,S‐Acetals

[(NHC)NiIIH]‐Catalyzed Cross‐Hydroalkenylation of Cyclopropenes with Alkynes: Cyclopentadiene Synthesis by [(NHC)NiII]‐Assisted C−C Rearrangement

Tandem Chemoselective 1,2‐/1,4‐Migration of the Thio Group in Keto Thioesters: An Efficient Approach to Substituted Butenolides

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[(NHC)Ni^IIH]‐Catalyzed Cross‐Hydroalkenylation of Cyclopropenes with Alkynes: Cyclopentadiene Synthesis by [(NHC)Ni^II]‐Assisted C−C Rearrangement