Simple and general synthesis of new 11H-11λ5-dibenzo[c,f][1,2,5]dithiaphosphepine derivatives

Transformations of benzothiadiphosphole system: General one‐pot synthesis of 1,2,5‐dithiaphosphepines and their precursor phosphanethiols

“…Recently, in order to find further information about this reaction, we have observed a new type of transformation which occurs when the intermediate A reacts with RMgBr with high steric hindrance of the R group (Scheme 3). In these cases (cases a, c, d), we have the prevalent formation [2] of the new heterocyclic compounds 8 (75-80%) with the concomitant formation of cyclic phosphane sulfides 9. When RMgX is sterically less demanding (case b) and the intermediate A was allowed to stand for about 3 h at room temperature before the reaction with RMgBr, we have the formation of both 8 and 4 in a ratio depending on the reaction time of the first step of the reaction with the formation of intermediate A.…”

“…It should be noted that the end product, phosphane sulfide D, was supposed [2] and never isolated but the subsequent isolation of phosphane 6 also confirms D.…”

“…According to spectral data their purity is higher than 98%. Characterization data for compounds 8a,c,d,e,f were reported previously [2]. CCDC 254796 contains the supplementary crystallographic data for this paper.…”

“…According to spectral data their purity is higher than 98%. Characterization data for compounds 8a,c,d,e,f were reported previously [2]. 2,2,5]dithiaphosphepine- 11-thione (8g).…”

“…In addition, cyclic systems containing both phosphorus and sulfur should be particularly interesting as bidentate or polydentate ligands but this type of compounds has received much less attention. Recently, in a communication we reported [2] a simple synthesis of the first examples of a new heterocyclic system, namely 11H-dibenzo[c,f][1, 2,5]dithiaphosphepine, containing in a seven-membered ring an S S unit and a P S group. Now, in this paper, we report further details of this new procedure to obtain new derivatives of this heterocyclic system and an Xray crystallographic study confirming the structure 339 previously proposed.…”