New synthesis of a seven member ring fused heterocycles using ring expansion reaction of an aromatic ring

(1)酮类与三甲基硅基重氮甲烷溴化镁盐（TMSCHN_2）反应生成2-重氮-2-（三甲基硅基）乙醇，该乙醇与乙炔通过1,3偶极环加成反应容易转化为吡唑。(2)在TMSCHN_2锂盐的催化下，芳基醛和杂芳基醛很容易在锅内转化为功能化的乙基。(3) TMSCHN_2与硫苯甲酰异氰酸酯反应生成相应的重氮酮，经醋酸铑处理后转化为2-氮杂氮烯。(4)重偶氮（三甲基硅基）甲基溴化镁与叔丁基芳基（氧）乙酸酯顺利反应，通过烷基烯碳烯中间体生成相应的芳基丙酸酯。(5)重氮（三甲基硅基）甲基溴化镁易于与酮类和醛类反应生成2-重氮-（2-三甲基硅基）乙醇，并与苯通过分子间[3+2]环加成有效地转化为具有3位羟基甲基的茚唑。(6)重偶氮（三甲基硅基）甲基溴化镁与（o-甲氧基苯基）（氧基）醋酸酯反应，通过最初生成的烷基烯碳烯中间体生成氧基溴化氢生成2-未取代苯并呋喃-3-羧酸盐。(7)三甲基硅基重氮甲烷锂与n -苄基-β-氨基酮在-78℃THF下反应得到3-取代1-苄基-3-（三甲基硅氧基）吡啶，产率中高。

(1) Ketones reacted with magnesium bromide salt of trimethylsilyldiazomethane (TMSCHN_2) to give the corresponding 2-diazo-2-(trimethylsilyl)ethanols which were easily converted to pyraazoles by 1,3-dipole cycloaddition the reaction with acetylenes. (2) Aryl and heteroaryl aldehydes were easily converted to functionalized acetykenes in on-pot using lithium salt of TMSCHN_2. (3) TMSCHN_2 reacted with thiobenzoyl isocyanates to give the corresponding diazoketones which were converted to 2-azaazulenes by treatment with rhodium acetates. (4) Diazo(trimethylsilyl)methylmagnesium bromide smoothly reacted with t-butyl aryl(oxo)acetates to afford the corresponding arylpropiolates via alkylidenecarbene intermediates. (5) Diazo(trimethylsilyl)methylmagnesium bromide readily reacted with ketones and aldehydes to give 2-diazo-(2-trimethylsilyl)ethanoles which were efficiently converted to indazoles bearing a hydroxmethyl unit at 3-position by intermolecular [3+2]cycloaddition with benzynes. (6) Diazo(trimethylsilyl)methylmagnesium bromide reacted with (o-methoxyphenyl)(oxo)acetates to readily afford 2-unsubstituted benzofuran-3-carboxylates via oxonium ylides formed from the initially generated alkylidenecarbene intermediates. (7) Lithium trimethylsilyldiazomethane reacted with N-benzyl-β-aminoketones at -78℃in THF to give 3-substituted 1-benzyl-3-(trimethylsiloxy)pyrrolidines in moderate to good yields.