Direct thiocyanations of benzylic compounds have been implemented. Here, a new strategy, involving a free radical reaction pathway initiated by AIBN, was used to construct the benzylic sp3 C–SCN bond. In this way, the disadvantage of other strategies involving introducing leaving groups in advance to synthesize benzyl thiocyanatecompounds was overcome. The currently developed protocol also involved
one-step synthesis of thiocyanates through C–O bond cleavage of readily available alcohols with ammonium thiocyanate as the thiocyanating agent was developed. The method avoids the use of additional catalyst, and a variety of (hetero)arene, alkene and aliphatic alcohols reacted with high efficiency in ethyl acetate under mild conditions to afford the corresponding thiocyanates in excellent to quantitative
Separate Deprotonation Reactions Converge Mechanistically for a New Cyclization of Benzyl 1-Alkynyl Sulfones
作者:M. Selim Hossain、Adrian L. Schwan
DOI:10.1021/ol202196y
日期:2011.10.7
A heretofore unknown LDA-induced conversion of benzyl 1-alkynyl sulfones to 1H-2-benzothiopyran-S,S-dioxides is demonstrated. A benzyl carbanion, accessible by two means, is thought to cyclize by temporary disruption of aromaticity. Key intermediates are observed by ReactIR analysis. Thiophene derivatives are also amenable to cyclization, forming 7H-thieno[2,3-c]thiopyran-S,S-dioxides.
证明了迄今为止未知的LDA诱导的苄基1-炔基砜向1 H -2-苯并噻喃-S,S-二氧化物的转化。苄基碳负离子可通过两种方式进入,被认为是由于芳香族的暂时破坏而环化的。通过ReactIR分析观察到了关键中间体。噻吩衍生物也适合环化,形成7 H-噻吩并[2,3- c ] thiopyran- S,S-二氧化物。
Selenonium Salt as a Catalyst for Nucleophilic Substitution Reactions in Water: Synthesis of Thiocyanites and Selenocyanates
作者:Alix Y. Bastidas Ángel、Philipe Raphael O. Campos、Eduardo E. Alberto
DOI:10.3390/molecules28073056
日期:——
interconversion and due to their biological activities. In this contribution, we report the synthesis of a series of these important substances in a mixture of water and dimethyl carbonate (20/1 proportion) using potassium thio- or selenocyanates salts and organic bromides. The key to the effectiveness of the reaction is a chalcogen bond interaction between a selenonium salt catalyst and the organic substrate