Ring-closing metathesis of diene

Scheme 6/3.23. Ring-closing metathesis of diene-ynes 6/3-78 in refluxing CH2CI2.

Ring-closing metathesis of diene 318 with a Grubbs second-generation catalyst gave 2,5-dihydropyrrole 319 (Equation 56). The absolute stereochemistry was assigned based on single crystal X-ray diffraction analysis... 

Fig. 3.50. The mechanism of ring-closing metathesis of dienes and enynes.

I 7 7 Polymer-supported Otejin Metathesis Catalysts for Organic and Combinatorial Synthesis Tab. 11.3 Recycling of Ru complex (16) in the ring-closing metathesis of diene (17). 

A concise stereoselective synthesis of a myoinositol derivative has been achieved by ring-closing metathesis of diene 21 prepared from a readily available bis-Weinreb amide 20 of D-tartrate [Eq. (6.19)]. ... 

Scheme 8.17 Ring closing metathesis of dienes with ruthenium-indenylidenes IX and XXV.

Ring closing metathesis of dienes to cyclic olefins CO2 Ruthenium catalyst... 

In Section III.A, it was shown how the ( - )-3,5,8,8a-tetrahydroindolizin-5-one 119 could be converted into (15,8aS)-( + )-indolizidin-l-ol (109) via epoxides 122 and 123 cf. Scheme 16). The same intermediates have also been transformed into (+ )-lentiginosine (132) and the unnatural 1,2-diepimer ( + )-160 (Scheme 23) (79). The enantiomer of the latter, (15,25,8a/f)-(-)-indolizine-l,2-diol ent-160), has been prepared by a route involving ring-closing metathesis of diene intermediate 161 91). 

MiUer SJ, Kim S-H, Chen Z-R, Gruhhs RH. Catalytic Ring-Closing Metathesis of Dienes Application to the Synthesis of Eight-Memhered Rings. J Am Chem Soc. 1995 117(7) 2108-2109. 

The total synthesis of alkaloid (+)-lycoricidine reported by Yadav et al. represents a further application of the sequence domino reductive fragmentation/allylation followed by ring-closing metathesis in the synthesis of bioactive natural products [42], Thus, reaction of co-iodoglycoside 29 with zinc/allyl bromide in THF/HjO afforded diene 30 (87%, dr 85 15). Ring-closing metathesis of diene 30 followed by acetylation furnished cyclohexene 31. Treatment of the acetate 31 with PhINTs in the presence of Cu(acac)2, followed by sodium naphthalenide, afforded the aziridine 32 (67%), from which (-i-)-lycoricidine (33) can be easily obtained (Scheme 3.11). 

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