Showing papers by "Teruaki Mukaiyama published in 1994"
TL;DR: In this article, an efficient method for the synthesis of macrolides directly from ω-hydroxycarboxylic acids was established by using 4-(trifluoromethyl)benzoic anhydride and a catalytic amount of active titanium(IV) salts together with chlorotrimethylsilane under mild conditions.
Abstract: An efficient method for the synthesis of macrolides directly from ω-hydroxycarboxylic acids is established by using 4-(trifluoromethyl)benzoic anhydride and a catalytic amount of active titanium(IV) salts together with chlorotrimethylsilane under mild conditions.
53 citations
TL;DR: In this paper, various carboxylic esters were prepared from nearly equimolar amounts of free carboxyl acids and alcohols at room temperature by combined use of 4-(trifluoromethyl)benzoic anhydride and a catalytic amount of active titanium(IV) salt together with chlorotrimethylsilane.
Abstract: Various carboxylic esters are prepared in excellent yields from nearly equimolar amounts of free carboxylic acids and alcohols at room temperature by combined use of 4-(trifluoromethyl)benzoic anhydride and a catalytic amount of active titanium(IV) salt together with chlorotrimethylsilane.
43 citations
TL;DR: In this article, N-alkyl imidazolems were used to achieve highly enantioselective epoxidation of olefins by combined use of molecular oxygen and pivalaldehyde with optically active Mn(III)-salen type catalysts.
Abstract: N-Alkyl imidazoles are effective axial ligands to achieve highly enantioselective epoxidation of unfunctionalized olefins by combined use of molecular oxygen and pivalaldehyde with optically active Mn(III)-salen-type complex catalysts. In the presence of N-alkyl imidazole, the epoxidation of 2,2-dimethylchromene proceeded smoothly to afford the corresponding optically active epoxide in 92% enantiomeric excess.
38 citations
TL;DR: In the presence of a catalytic amount of [(R)-1,1′-bi-2-naphthalenediolato(2-)-O,O′]oxotitanium, silyl enol ethers of thioesters reacted with α,β-unsaturated ketones to afford the corresponding Mic...
Abstract: In the presence of a catalytic amount of [(R)-1,1′-bi-2-naphthalenediolato(2-)-O,O′]oxotitanium, silyl enol ethers of thioesters reacted with α,β-unsaturated ketones to afford the corresponding Mic...
37 citations
31 citations
TL;DR: 今で もその時の光景が頭 に浮かぶ, で も元 気 の よい若者たちが溢れて いた実験室, 今 度は 目 的のア ミ ドが全 られ なか った.
Abstract: 今で もその時の光景が頭 に浮かぶ.学 習院大学の昔の 理学部 化学科(1955年)の 古 めか しい,狭 い, で も元 気 の よい若者たちが溢れて いた実験室. フラス コの中で全 く考 えも しなか った現象が観察 され た. 激 し くガスが飛 び,褐 色 に変化す る溶液か ら沈殿が出 る.こ こで観察 された泡 の中に, 全 く予想 も しない, 思 い もよらない大 きな夢 が秘 め られ ていた.α-ニ トロ酢 酸 アニ リ ドの合成 を試 みたこ とが契機 であった.文 献で 知 られている既知 の方法 によってフェニルイソシアナー トとニ トロメタ ンのナ トリウム塩 の付加反応 によって合 成 を試 みたところ,約20%の 収率 で 目的物が得 られた. この時点 では反応機構 の解 明を主な研 究課題 としていた ので, そのための試料 が入手 で きれば よい とい う考 えで あったため,収 率 が悪 くて も,ど の ような副生成物が で きているか とい うことを特に追求 しなか った.次 に同族 体 であ る α-ニトロプロ ピオ ン 酸 アニ リ ドを合成す るこ とにな り,前 例 に習 いニ トロエ タンのナ トリウム塩 と フェニル イソシアナ ー トを反応 させた ところ,今 度は 目 的のア ミ ドが全 く得 られ なか った.こ の ように 目的物が 全 く得 られない段 階で, 考 えを新た に していろいろ実験 条件 を検討 してい くうちに,つ い に反応 中間体 としてア ルキルニ トリル オキ シ ドが生成す るとい う新 しい事実 を
28 citations
TL;DR: In this paper, an efficient synthesis of acid-sensitive epoxides, such as chromene oxide or epoxide of γ,δ-unsaturated alcohol, was successfully achieved by the oxygenation of corresponding olefins with the combined use of an atmospheric pressure of molecular oxygen and aldoacetal catalyzed by a cobalt(II) complex coordinated with the 1,3-diketone ligand.
Abstract: An efficient synthesis of acid-sensitive epoxides, such as chromene oxide or epoxide of γ,δ-unsaturated alcohol, was successfully achieved by the oxygenation of corresponding olefins with the combined use of an atmospheric pressure of molecular oxygen and aldoacetal catalyzed by a cobalt(II) complex coordinated with the 1,3-diketone ligand. The reactions proceeded under mild and neutral conditions, and the desired epoxides were obtained in good yields. Neither overoxidation nor decomposition of the formed epoxide was observed under the present reaction conditions. Furthermore, various silyl enol ethers and silyl ketene acetals, acid-sensitive compounds, were also smoothly monooxygenated into the corresponding α-hydroxy ketones and α-hydroxy carboxylic acid esters, respectively.
27 citations
TL;DR: In this article, the synthesis of β-D-Ribofuranosides from 2,3,5-tri-O-benzyl-1,O-iodoacetyl-Dribofuranose (1) and trimethylsilylated nucleophiles by the use of silver salts in the coexistence of 3 molar amounts of lithium perchlorate was described.
Abstract: α-D-Ribofuranosides are stereoselectively synthesized in high yields from 2,3,5-tri-O-benzyl-1-O-iodoacetyl-D-ribofuranose (1) and trimethylsilylated nucleophiles by the use of silver salts in the coexistence of 3 molar amounts of lithium perchlorate, while β-D-ribofuranosides are prepared predominantly in high yields by the reaction of 1 and trimethylsilylated nucleophiles or 2,3,5-tri-O-benzyl-D-ribofuranose and free alcohols by using [diphenyltin sulfide/silver salt] or [Lawesson’s reagent/silver salt] combined catalyst system.
18 citations
TL;DR: In the presence of a catalyst generated from SnCl4 and AgClO4, or Yb(OTf)3 various glycosyl azides are synthesized in high yields with complete stereoselectivities from peracylated sugars and trimethylsilyl azide by choosing a suitable solvent such as dichloromethane or nitromethane as discussed by the authors.
Abstract: In the presence of a catalyst generated from SnCl4 and AgClO4, or Yb(OTf)3 various glycosyl azides are synthesized in high yields with complete stereoselectivities from peracylated sugars and trimethylsilyl azide by choosing a suitable solvent such as dichloromethane or nitromethane.
16 citations
TL;DR: In this article, β-D-Ribonucleosides are synthesized from methyl 2,3,5-tri-O-benzoyl-β-Dribofuranosyl carbonate and trimethylsilylated nucleoside bases by the use of [diphenyltin sulfide/ silver salt] or [Lawesson's reagent/silver salt] combined catalyst system under mild conditions.
Abstract: β-D-Ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases by the use of [diphenyltin sulfide/silver salt] or [Lawesson’s reagent/silver salt] combined catalyst system under mild conditions.
11 citations
TL;DR: In this paper, the synthesis of D-ribofuranosides from 2,3,5-tri-O-benzyl-1,O-iodoacetyl-Dribofuranose and trimethyl-silylated nucleophiles such as 3β-cholestanyl trimethylsilyl ether and phenyl trimethyl sulfide is efficiently promoted by tin(II) chloride under mild conditions.
Abstract: Catalytic synthesis of several D-ribofuranosides from 2,3,5-tri-O-benzyl-1-O-iodoacetyl-D-ribofuranose and trimethylsilylated nucleophiles such as 3β-cholestanyl trimethylsilyl ether and phenyl trimethylsilyl sulfide is efficiently promoted by tin(II) chloride under mild conditions. When allyltrimethylsilane, azidotrimethylsilane, etc., are used as nucleophiles, combined use of catalytic amounts of SnCl2 and SiCl4 also afforded the corresponding ribofuranosides in good yields.
TL;DR: In this article, aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) under mild conditions.
Abstract: Catalytic aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.
Journal Article•
TL;DR: Several β-D-ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-Dribofuranosyl carbonate as mentioned in this paper.
Abstract: Several β-D-ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases such as pertrimethylsilylated uracil and adenine under mild conditions by using a catalytic amount of tin(II) chloride, a weak Lewis acid.
TL;DR: In the presence of a catalyst generated from SnCl4 and AgClO4, or Yb(OTf)3 various glycosyl azides are synthesized in high yields with complete stereoselectivities from peracylated sugars and trimethylsilyl azide by choosing a suitable solvent such as dichloromethane or nitromethane as mentioned in this paper.
Abstract: In the presence of a catalyst generated from SnCl4 and AgClO4, or Yb(OTf)3 various glycosyl azides are synthesized in high yields with complete stereoselectivities from peracylated sugars and trimethylsilyl azide by choosing a suitable solvent such as dichloromethane or nitromethane.
Journal Article•
TL;DR: In this article, a catalytic synthesis of β-D-ribofuranosides from C-1 free ribofuranose, 2,3,5-tri-O-benzyl-Dribofuranoses, and alcohols is efficiently performed by combined use of silver salts and Lawesson's reagent.
Abstract: Catalytic synthesis of β-D-ribofuranosides from C-1 free ribofuranose, 2,3,5-tri-O-benzyl-D-ribofuranose, and alcohols is efficiently performed by combined use of silver salts and Lawesson’s reagent, [2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide], or silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.
TL;DR: In this article, various carboxylic esters were prepared from nearly equimolar amounts of free carboxyl acids and alcohols at room temperature by combined use of 4-(trifluoromethyl)benzoic anhydride and a catalytic amount of active titanium(IV) salt together with chlorotrimethylsilane.
Abstract: Various carboxylic esters are prepared in excellent yields from nearly equimolar amounts of free carboxylic acids and alcohols at room temperature by combined use of 4-(trifluoromethyl)benzoic anhydride and a catalytic amount of active titanium(IV) salt together with chlorotrimethylsilane.
TL;DR: In the presence of a catalyst generated from SnCl4 and a silver salt, various 2-amino-2-deoxy-α-D-glucopyranosides or galactopyranoides are stereoselectively synthesized as mentioned in this paper.
Abstract: In the presence of a catalyst generated from SnCl4 and a silver salt, various 2-amino-2-deoxy-α-D-glucopyranosides or galactopyranosides are stereoselectively synthesized in good yields with high stereoselectivities through anomerization step starting from 1,3,4,6-tetra-O-acetyl-2-deoxy-2-(2,2,2-trichloroethoxycarbonylamino)-β-D-glucopyranose or galactopyranose and alkyl trimethylsilyl ethers, respectively.
TL;DR: In this paper, aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) under mild conditions.
Abstract: Catalytic aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.
TL;DR: In this paper, the synthesis of ribonucleosides from 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl methyl carbonate and trimethylsilylated nucleoside bases is efficiently carried out by combined use of silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.
Abstract: Catalytic stereoselective synthesis of several ribonucleosides from 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl methyl carbonate and trimethylsilylated nucleoside bases is efficiently carried out by combined use of silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.
TL;DR: In this article, the authors described new and effective aerobic oxygenation reactions of olefins catalyzed by transition-metal complexes using an atmospheric pressure of molecular oxygen and secondary alcohols.
Abstract: New and effective aerobic oxygenation reactions of olefins catalyzed by transition-metal complexes are described (1) By the combined use of an atmospheric pressure of molecular oxygen and secondary alcohols, various kinds of olefins are converted into the corresponding alcohols in good to high yields catalyzed by a cobalt (II) complex (2) Effective epoxidation of a wide variety of olefins involving styrenes and α, β-unsaturated carboxamide are achieved by the combination use of aldehyde and molecular oxygen catalyzed by nickel (II), iron (III), or oxovanadium (IV) complexes under mild reaction conditions (3) Enantioselective aerobic epoxidations of unfuctionalized olefins are demonstrated by using optically active manganese (III) complexes as catalysts (4) In the presence of acetal of aldehyde, cobalt (II) complex catalyzed aerobic epoxidation of olefins proceeds in high yield under neutral and mild conditions
TL;DR: In this article, the synthesis of D-ribofuranosides from 2,3,5-tri-O-benzyl-1,O-iodoacetyl-Dribofuranose and trimethyl-silylated nucleophiles such as 3β-cholestanyl trimethylsilyl ether and phenyl trimethyl sulfide is efficiently promoted by tin(II) chloride under mild conditions.
Abstract: Catalytic synthesis of several D-ribofuranosides from 2,3,5-tri-O-benzyl-1-O-iodoacetyl-D-ribofuranose and trimethylsilylated nucleophiles such as 3β-cholestanyl trimethylsilyl ether and phenyl trimethylsilyl sulfide is efficiently promoted by tin(II) chloride under mild conditions. When allyltrimethylsilane, azidotrimethylsilane, etc., are used as nucleophiles, combined use of catalytic amounts of SnCl2 and SiCl4 also afforded the corresponding ribofuranosides in good yields.