Science of Synthesis

Gandon, V.; Thorimbert, S.; Malacria, M., Science of Synthesis, (2009) 46, 221.

During the course of investigations into palladium-catalyzed enyne metathesis it was reported that the use of diacetoxybis(triphenylphosphine)platinum associated with dimethyl acetylenedicarboxylate allows the production of vinylcyclopentenes,[‌149‌] and in 1996 it was shown that platinum(II), platinum(IV), and gold(III) chlorides can be employed for the skeletal reorganizations of 1,6- and 1,7-enynes to give 1-vinylcycloalkenes.[‌156‌] Other platinum complexes, such as dichlorobis(triphenylphosphine)platinum(II) or dichlo­ro(cyclooctadiene)platinum(II), have no catalytic activity in such procedures, which suggests that, although chloride is necessary, electron-rich ligands should be absent. Since this pioneering work was carried out, spectacular efforts have been made by chemists to explore the behavior of platinum complexes[‌157‌–‌159‌] and gold salts,[‌160‌–‌162‌] and the mechanisms of these skeletal reorganizations have been subjected to both experimental and theoretical scrutiny.[‌163‌–‌167‌] Moreover, these transformations are utilized in some elegant natural product syntheses;[‌151‌,‌168‌] most of this chemistry has already been reviewed.[‌169‌–‌172‌] The first cyclizations to be described were performed on simple enynes ‌164‌ in the presence of platinum(II) chloride as the catalyst and toluene as the solvent (‌Scheme 58‌, Method A).[‌156‌–‌158‌] Other solvents such as tetrahydrofuran, dimethylformamide, cyclohexane, or dioxane prove to be less suitable giving the expected dienes ‌165‌ in low yields, together with other 1,4-dienes.[‌156‌,‌173‌] Cationic gold complexes are also good catalysts for these cycloisomerizations (‌Scheme 58‌, Method B).[‌160‌]

‌Meeeee 88‌ Meeeeeee- eee Meee-Meeeeeeee Meeeeeeeeeeeeeeeee ee Meeeee 8,8-Meeeee Me Meee 8-Meeeeeeeeeeeeeeeee[‌888‌–‌888‌,‌888‌]

‌Meeeeeeeeee 88‌

Mee eeeeeeee ee e eeeeeeeeee ee eee eeeeee eeeeeee eee eeeeeee eee eeee eeeee eeeeeee eeeeeeee eee eeeeeeeee ee eee eeeeeeee 8-eeeeeeeeeeeeeeeeee; eee eeeeeee, eee eeeeeeeeeee ‌888‌ eeeee eeeeeeeeeeeee eee eeeeeeeeeeeeeeeeeeee ‌888‌ eeeeee eeee eee 8-eeeee-8,8-eeeeeeeeeeeeee ‌888‌, eeeeeee eee eeeeeeeeeeeeeeeeee ‌888‌ eeeeeeeee eeee eee eeee-eeeee eeeeeeeeeeee ‌888‌ (‌Meeeee 88‌).[‌888‌]

‌Meeeee 88‌ Meeeeeeeeee Meeeeeeeeeeeeeee Meeeeeeee ee eee Meeeeeee-Meeeeeeee Meeeeeeeeee ee 8,8-Meeeee[‌888‌]

Mee eeeeeeeeee ee eeeeeee ee eeeeeeeee eeeeeeeeeee eee, eeeeeeeee eeee eee eeeeee ee eee eeeeeeeeee eeeee eeeeee ee eee eeeeee eeee ee eee eeeeeeeeeee eeeeeeee, e eeeeeeeeeee eeeeeeeee eeeeeeee ee eeeeeeeeeeeeeeee eee ee eeeeeeee.[‌888‌,‌888‌] Mee eeeeeee, eeeeeeeee ee eee eeeeeee ‌888‌ eeee eeeeeeee(MM) eeeeeeee eeeee e eeeeeee ee eee eeeeeee ‌888‌ eee eee eeeeeeeeeeee ‌888‌ ee e 8:8 eeeeeee eeeee (‌Meeeee 88‌).[‌888‌]

‌Meeeee 88‌ Meeeeeeeeee Meeeeeeee/Meeeeeeeeeeeeeee ee eee Meeeeeee-Meeeeeeee Meeeeeeeeee ee 8,8-Meeeeeeeeeee-8-ee-8-ee-8-ee Meeeeee[‌888‌]

Mee eeeeeeeee- ee eeeeeeee-eeeeeeeee eeeeeeeeeeeeeeeeee ee 8,8-eeeeee ‌888‌ eeeeee e eeeeee eeeeee eeeeeeeee ee e eeeeeeeee eeeeeeeeee eee eeeeeeeee eeeeeeee ee eeeeeeee eeeeee ‌888‌ (‌Meeeee 88‌).[‌888‌,‌888‌,‌888‌] Meeeeeeeeee eeeeeeeeee eeeeeeeeee eee eeeeeeeee eee eeeeeeeee eeeeeeeeee eeeeee eee eeeeeeeee, eeeeeeeee eeeeee, eeeeee, eeeeeeee, eee eeeeeeeeeeee; eeeeeeee, eee eeeeeeeeeee eeeeeeee eeee eeee eeeeeeeeeeee ee eeeeeeeee eeee eeee.

‌Meeeee 88‌ Meeeeeee-Meeeeeeee Meeeeeeeeeeeeeeeee ee 8,8-Meeeee Meeeee e Meeeeeeeeee Meeeeeeee[‌888‌,‌888‌–‌888‌,‌888‌]

‌Meeeeeeeeee 88‌

Meeeeeeeeeee Meeeeeeee

8-[88-Meeee-88-eeeeeeeeee[8.8.8]-eeeeee-8(88),8-eeee-8-ee]eeeee-8-eee (‌888‌, M8 = MMMe; M = MMe; e = 8); Meeeeee Meeeeeeee:[‌888‌]

MeMe8 (888 ee, 8.88 eeee, 8 eee%) eee eeeee ee eee eeeee ‌888‌ (M8 = MMMe; M = MMe; e = 8; 8.88 e, 8.88 eeee) ee eeeeeee (888 eM) eee eee eeeeee-eeeee eeeeeeeee eeee eeee eeeeee eee eeeeee ee 88°M eee 88 e. Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (eeeeee eee, eeeeeee/MeMMe 8:8 ee 8:8) ee eeee e eeeeee eeeeee eeeee; eeeee: 8.88 e (88%).

References