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

由炔烃生成亚烷基和亚乙烯基络合物的一般原理被发现适用于过渡金属催化的反应。在三乙胺存在下，预先形成的π-烯烃络合物发生分子内环化或迁移得到亚烷基-或亚乙叉-2-吡喃-铬络合物。我们证明了在三乙胺存在下，(β-乙炔-α，β-不饱和酯和酰胺)合成了2-吡喃-亚甲基铬络合物。铬-偏二亚甲基络合物是反应中的关键中间体。将该方法应用于顺-L-乙炔基-2-酰基环丙烷，提供了一种新的催化芳构化反应，通过环丙基亚乙叉生成邻位取代苯酚。与之形成鲜明对比的是，β-乙炔基-α，β-不饱和酮与M(CO)_5(THF)(M=Cr，W)反应，通过羰基氧对π-炔基配合物的亲核攻击，选择性地合成了(2-呋喃)卡宾配合物。这种(2-呋喃)卡宾络合物已很好地应用于β-乙炔-α，β-不饱和…催化反应在烯烃的环丙烷化、与杂原子的卡宾转移反应以及与碳氢化合物的插入反应中，更多的酮已被证明。从相应的β-乙炔基-α，β-不饱和亚氨基化合物中合成了杂芳环取代的卡宾物种，即(2-吡咯基)卡宾，应用于炔丙基羧酸盐为过渡金属的乙烯基卡宾提供了新的途径。因此，在丙叉基底物的π-络合物中，羰基氧对内部碳的亲核攻击，然后在丙叉位置发生键断裂，得到了乙烯基卡宾络合物。广泛的过渡金属络合物是实现这一目的的有效途径。特别地，[RuCl2(CO)3]2络合物作为催化剂可以促进烯烃分子间的环丙烷化反应，以丙叉羧酸盐为乙烯基卡宾的前体。共轭双烯与丙叉基底物反应，通过环丙烷化和随后的[3，3]Sigma重排得到七元环。较少

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