5.7. [32π + 32σ] Cycloadditions 74 5.8. [44π + 22π] Cycloadditions 75 6. Seven-Membered Ring Formation 78 6.1. [44π + 32σ] Cycloadditions 78 6.2. [52π+2σ + 22π] Cycloadditions 79 7. Eight-Membered Ring Formation 79 7.1. [22π + 22π + 22π + 22π] Cycloadditions 80 7.2. [44π + 22π + 22π] Cycloadditions 80 7.3. [44π + 44π] Cycloadditions 81 7.4. [66π + 22π] Cycloadditions 83 8. Ten-Membered Ring Formation 85 9. Conclusion and Remarks 87

Transition Metal-Mediated Cycloaddition Reactions

Organopalladium intermediates in organic synthesis

The tremendous potential of cyclopropenes and methylene-cyclopropanes as multifunctional reagents in organic syntheses has only been recognized in the last decade. The use of transition metal catalysts allows an effective control of their transformations enabling highly selecitive syntheses ranging from three- to sevenmembered carbocycles. The activities in this field are summarized in this review for the first time with an emphasis on the preparative aspects of this work.

Cyclopropenes and methylenecylopropanes as multifunctional reagents in transition metal catalyzed reactions

The reaction of allylstannanes 1 with aldehydes 2 in THF was catalyzed by Pd(II) or Pt(II) complexes (10 mol %) either at room temperature or at reflux, giving the corresponding homoallylic alcohols 3 in high to good yields. Among the catalysts examined, PtCl2(PPh3)2 gave the best result. No only allyltribitylstannane but also methallyl- and crotyltributylstannane could be utilized in this transition metal catalyzed reaction. Detailed mechanistic studies of the Pd(II)-catalyzed allylation, using NMR spectroscopy, revealed that the bis-π-allylpalladium complex is a key intermediate for the catalytic cycle and it exhibits nucleophilic reactivity. The nucleophilic reactivity of the intermediate is in marked contrast to the electrophilic reactivity of ordinary π-allylpalladium complexes (π-allylPdX, X = OAc, halogen, OCO2R, etc.). The addition of allyl-, crotyl-, and methallylstannanes to various imines 4 proceeded very smoothly to give the corresponding allylated products (homoallylic amines 5) in good to hi...

Palladium- and Platinum-Catalyzed Addition of Aldehydes and Imines with Allylstannanes. Chemoselective Allylation of Imines in the Presence of Aldehydes

57 – Organopalladium Compounds in Organic Synthesis and in Catalysis

Organic syntheses by means of noble metal compounds—XLVII : Reaction of butadiene with aldehydes and ketones catalyzed by palladium-phosphine complexes

T. Mitsuyasu

Papers

Organic syntheses by means of noble metal compounds—XLVII : Reaction of butadiene with aldehydes and ketones catalyzed by palladium-phosphine complexes

Organic synthesis by means of noble metal compound—LI