N‐Iodosuccinimide: A Highly Effective Regioselective Reagent for Iodoesterification of Alkenes

A rapid, convenient, and efficient method has been achieved for regioselective iodoesterification of alkenes with aliphatic and aromatic acids, and protected amino acids in the presence of N‐iodosuccinimide (NIS) in nearly quantitative yields. Optically enriched iodohydrins have been achieved by LiAlH₄ (LAH) reduction of diastereoisomeric iodo esters.     

New entry to the Pauson-Khand reaction: trimethylgermyl group at the triple bond terminus as a latent functional group

The Pauson-Khand reaction of enynes possessing a trimethylgermyl group at the alkyne terminus afforded the corresponding bicyclo[3.3.0]octenone and bicyclo[4.3.0]nonenone skeletons in a stereoselective manner. The resulting trimethylgermyl group of the bicyclic compounds was then converted to the iodo group, which was used for further elaboration. Thus, the trimethylgermyl group at the triple bond terminus was shown to be a precursor for other appendages.     

d(x2-y2)+idxy混合波正常金属/绝缘层/超导体结中的隧道谱

考虑界面粗糙散射,在Blonder-Tinkham-Klapwijk(BTK)理论框架下,通过求解Bogoliubov-de-Gennes(BdG)方程,分别计算T=0K和有限温度下,d_(x²-y²)+id_xy混合波正常金属绝缘层超导体结中的准粒子输运系数和隧道谱.研究表明:隧道谱中的电导峰的劈裂程度强烈地依赖于d_xy波分量的强度、超导体的晶轴方位和界面粗糙强度,而温度的升高能压低电导峰. 关键词： NIS结 (x²-y²)+id_xy混合波超导体')" href="#">d_(x²-y²)+id_xy混合波超导体 隧道谱     

Ring opening of activated cyclopropanes with NIS/NaN3: synthesis of C-1 linked pseudodisaccharides

NIS/NaN₃ mediated ring opening of various donor–acceptor cyclopropanes has been investigated. The study shows the necessity of the donor oxygen lone pair in such ring opening reactions. This methodology has been utilized in the synthesis of C-1 linked pseudodisaccharides through the use of click chemistry.     

NBS or DEAD as effective reagents in α-thiocyanation of enolizable ketones with ammonium thiocyanate

Ketones possessing α-hydrogen undergo smooth thiocyanation with ammonium thiocyanate in the presence of N-bromosuccinimide (NBS) at room temperature in acetonitrile under neutral conditions to produce the corresponding α-ketothiocyanates in excellent yields with high selectivity. The use of NBS makes this procedure simple, convenient and cost effective. In addition, diethyl azodicarboxylate (DEAD) was also found to promote this reaction under mild conditions.     

正常金属/绝缘层/s波超导隧道结中绝缘层对微分电导的影响

在正常金属／绝缘层／s波超导隧道结（NIS结）中，以方势垒描述绝缘层对准粒子输运的影 响，运用Bogoliubov_de Gennes（BdG）方程、Blonder_Tinkham_Klapwijk(BTK)理论，计算 了NIS隧道结中的准粒子输运系数和微分电导.研究表明,微分电导随绝缘层厚度的变化呈振 荡和衰减两种趋势，其振荡的周期和衰减的快慢均强烈地依赖于绝缘层的势垒值以及V=Δ ₀/e的偏压值，电导峰的高低及峰的位置与绝缘层厚度密切相关，显示了比δ势 描述更为丰富多彩的隧道谱. 关键词： NIS结 方势垒 微分电导     

Glycosylation reactions with ‘disarmed’ thioglycoside donors promoted by N-iodosuccinimide and HClO4-silica

Glycosylation of ‘disarmed’ thioglycosides promoted by NIS in the presence of HClO₄ immobilized on silica compares very favourably with the accepted NIS-TfOH procedure.     

Base-free NIS promoted electrophilic cyclization of alkynes: an efficient synthesis of iodo substituted pyrano[4,3-b]quinolines

A simple and mild procedure for the synthesis of iodo substituted 1H-pyrano[4,3-b]quinolines has been achieved using NIS reagent in the absence of base from 2-alkynylquinoline-3-carboxaldehydes via intramolecular electrophilic cyclization onto alkynes in good to excellent yields in a short duration of time. The reactions proceeded smoothly in a normal solvent in aerobic atmosphere at room temperature. The presence of substituent at either quinoline or alkyne moieties did not show effect on reaction rate of cyclization. The palladium-catalyzed transformations of iodo group to C-C bond are also discussed.     

Photoinduced cyclization of alkynoates to coumarins with N-Iodosuccinimide as a free-radical initiator under ambient and metal-free conditions

An efficient photoinduced strategy for the preparation of coumarins was developed. In the presence of N-iodosuccinimide (NIS) as a free-radical initiator and under LED (380–385?nm) irradiation and metal-free conditions, the reaction of alkynoates underwent smoothly to afford the corresponding coumarins in high yields at room temperature with broad substrate scope via free radical intramolecular cyclization and ester rearrangement.