Development of New Catalytic Reactions Based on Novel Approach for Carbene Complexes

从炔烃生成亚烷基和亚乙烯基络合物的一般原理被发现应用于过渡金属催化的反应。在三乙胺存在下，由β-乙炔基-α，β-不饱和酯和酰胺合成了2-吡喃亚基-铬配合物。铬-亚乙烯基络合物是反应中的关键中间体。将该方法应用于顺式-1-乙炔基-2-酰基环丙烷的催化芳构化反应，提供了一种新的催化芳构化反应，通过环丙基亚乙烯基生成邻位取代苯酚。与此相反，β-乙炔基-α，β-不饱和酮与M（CO）_5（THF）（M=Cr，W）反应，通过羰基氧亲核进攻π-炔配合物，选择性地得到了2-呋喃基卡宾配合物。这种（2-呋喃基）卡宾络合物的形成已很好地应用于使用β-乙炔基-α，β-不饱和 关于我们 酮，其中烯烃的环丙烷化、与杂原子的卡宾转移反应和与烃的插入反应已经被证明。从相应的β-乙炔基-α，β-不饱和亚氨基化合物出发，还合成了芳杂环取代的卡宾类化合物，即（2-吡咯基）卡宾，并将其应用于炔丙基羧酸酯，为过渡金属的乙烯基卡宾化合物的合成提供了新的途径。因此，羰基氧对炔丙基底物的π-络合物中的内部碳的亲核攻击，然后在炔丙基位置处进行键断裂，得到乙烯基卡宾络合物。广泛的过渡金属络合物对于该目的是有效的。特别是[RuCl_2（CO）_3]_2配合物作为催化剂可以促进炔丙基羧酸酯作为乙烯基卡宾前体的烯烃分子间环丙烷化反应。共轭二烯与炔丙基底物的反应通过环丙烷化和随后的[3，3] σ转移重排得到七元环。少

General principles for generating alkylidene-and vinylidene-complexes from alkynes were found to apply ~to transition metal-catalyzed reactions. Intramolecular cyclization or migration in pre-formed π-alkyne complexes occurs to give an alkylidene-or a vinylidene-complex.We have demonstrated that 2-pyranylidene-chromium complexes were prepared from (β-ethynyl-α,β-unsaturated esters and amides in the presence of triethylamine. A chromium-vinylidene complex is a key intermediate in the reaction. Application of this protocol to cis-l-ethynyl-2-acylcyclopropane provided a new catalytic aromatization reaction leading to o-substituted phenol via cyclopropylvinylidenes. In sharp contrast, the reaction of β-ethynyl-α,β-unsaturated ketones with M(CO)_5(THF) (M=Cr, W) gave, (2-furyl)carbene complexes selectively via nucleophilic attack of a carbonyl oxygen to a π-alkyne complex. This (2-furyl)carbene complex formation has been nicely applied to catalytic reactions using β-ethynyl-α,β-unsaturated … More ketones, in which cyclopropanation of alkenes, carbene transfer reactions with heteroatoms, and insertion reactions with hydrocarbons have, been demonstrated. Heteroaromatic ring-substituted carbene species, i.e. (2-pyrrolyl)carbenoids were also prepared from the corresponding β-ethynyl-α,β-unsaturated imino compounds.Application to propargylic carboxylates has provided new access to vinylcarbenoids of transition metals. Thus, the nucleophilic attack of a carbonyl oxygen to an internal carbon in π-complexes of propargylic substrates followed by bond cleavage at propargylic position gave vinylcarbene complexes. A wide range of transition metal complexes is effective for the purpose. Particularly, a [RuCl_2(CO)_3]_2 complex as a catalyst can promote the intermolecular cyclopropanation of alkenes using propargylic carboxylates as precursors of vinylcarbenoids. The reaction of conjugated dienes with propargylic substrates afforded seven-membered rings via cyclopropanation and subsequent [3,3]sigmatropic rearrangement. Less