- 2-Iodoxybenzoic acid organosulfonates: Preparation, X-ray structure and reactivity of new, powerful hypervalent iodine(v) oxidants
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New powerful hypervalent iodine(v) oxidants, tosylate and mesylate derivatives of 2-iodoxybenzoic acid (IBX), were prepared by the reaction of IBX with the corresponding sulfonic acids. Single crystal X-ray crystallography of the diacetate derivative of IBX-tosylate revealed an unusual heptacoordinated iodine geometry without any significant intermolecular secondary interactions.
- Yusubov, Mekhman S.,Svitich, Dmitrii Yu.,Yoshimura, Akira,Nemykin, Victor N.,Zhdankin, Viktor V.
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p. 11269 - 11271
(2013/12/04)
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- Medium-ring Ketone Synthesis. Synthesis of Eight- to Twelve-membered Cyclic Ketones based on the Intramolecular Cyclization of Large-Membered Lactam Sulfoxides or Sulfones
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An effective general method for the construction of medium-ring ketones from the corresponding ω-bromocarboxylic acids is described.When the diamide disulfide 10 was treated with NaBH4 and NaH in 2-propanol, reductive cleavage of the sulfur-sulfur bond and concomitant intramolecular coupling of the resulting thiolate anion with the terminal bromide took place and the large-ring lactam sulfide 7, which was the key intermediate for the synthesis of medium-ring ketones, was obtained.Although lithium diisopropyl amide (LDA) treatment of 11 followed by reductive desulfurization provided cycloundecanone (13d) in only 19.5percent yield, intramolecular cyclization of the α-methylated analogues 17 with LDA proceeded smoothly and the keto sulfoxides 18 were obtained in quantitative yields.In the case of the lactam sulfones 21, tert-BuOK was effective as a base for the intramolecular cyclization, affording the keto sulfones 22 in quantitative yields.The keto sulfoxides 18 and sulfones 22 were subjected to reductive desulfurization with Al-Hg to yield medium-ring ketones 19 and 13, respectively, in high yields.Keywords - medium-ring ketone; intramolecular cyclization; large-ring lactam sulfide; bis(2-methylaminophenyl) disulfide; 2-methylaminobenzenethiol; reductive desulfurization; sulfur-stabilized carbanion; active methylene
- Ohtsuka, Yasuo,Oishi, Takeshi
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p. 454 - 465
(2007/10/02)
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