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Carbene Addition to C=C Bonds

Carbene Addition to C=C Bonds. Generation of carbenes. Electronic Structures of Carbenes. q ’. q. arylcarbenes cycanocarbene alkynylcarbene. :CF 2 :CCl 2 :CBr 2 :CHCO 2 R. :CH 2 ( q ' > q ). 130~150°. 100~110°. cis -olefin. cis -cyclopropane. Retentive stereochemistry. spin

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Carbene Addition to C=C Bonds

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  1. Carbene Addition to C=C Bonds Generation of carbenes

  2. Electronic Structures of Carbenes q’ q arylcarbenes cycanocarbene alkynylcarbene :CF2 :CCl2 :CBr2 :CHCO2R :CH2 (q'>q) 130~150° 100~110° cis-olefin cis-cyclopropane Retentive stereochemistry

  3. spin inversion

  4. Orbital Interaction Between Carbene and Olefin > more stable asymmetrical transition state symmetrical transition state Reaction of Conjugate Dienes (cisoid) with Singlet Carbenes

  5. p–pand s–p* interactions between singlet carbenes and olefins reactive both to electron rich and deficient olefins Electrophilic nucleophilic

  6. Typical carbene reactions a-elimination Ph:

  7. a-elimination insersion Reimer-Tiemann reaction

  8. Nitrene isocyanate

  9. Electrophilic organometallic reagents the carbon-metal bond: highly polarized the carbon-halogen bond: highly polarized Simmons-Smith Reagent Carbene Metal Complexes

  10. Carbenoids: Electrophilic and Nucleophilic Properties nucleophilic carbenoid electrophilic carbenoid

  11. The first catalytic asymmetric reaction of prochiral compounds caused by soluble chiral metal complexes Nozaki, H.; Moriuchi, S.; Takaya, H., Noyori, R.Tetrahedron Lett. 1966, 5239 銅－カルベン錯体 (Simmons-Smith)

  12. 野依触媒 顕谷触媒 パーメスリン酸 シラスタティン

  13. Alkene metathesis Mechanism [2 + 2] Metal-carbene complex metallacyclobutane

  14. Evidence supporting Chauvin mechanism

  15. Addition of Radicals to C=C Bonds without peroxide Markovnikov rule: carbenium ion stability Ionic process hyperconjugation with peroxide anti-Markovnikov rule: radical stability radical process Mechanism:radical chain process

  16. Gomberg, 1900; "persistent hydrocarbon radical" "persistent hydrocarbon radical" radical with shelf-storable stability LUMO of acceptor SOMO of radical DPPH HOMO of donor capto-dative radical

  17. Some previous observations difficult to explain . fast . . minor major slow Recent findings to explain these previous issues

  18. Reasonable explanation for alternative co-polymerization: Why the reaction proceeds in such a way? Polymer)n Polymer)n+1 Favorable orbital interactions are highly specific !! LUMO LUMO SOMO SOMO HOMO HOMO

  19. Structures of Radicals

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