Synthesis and reactions of 1,6-dithiocyanato- and 1,6-diiodo-1,3,5-cycloheptatrienes

Abstract

Photoreactions of benzocyclopropene (1) with thiocyanogen and iodine afforded 1,6-dithiocyanato-( 4) and 1,6-diiodocycloheptatriene (7), respectively, in good yields, whereas thermal reactions gave 2-thiocyanatobenzyl thiocyanate (5) and 2-thiocyanatobenzyl isothiocyanate (6) from thiocyanogen and 2-iodobenzyl iodide (8) from iodine. Disodium 1,3, obtained by reduction of 4 with sodium in liquid ammonia was converted into mediumto large-membered ring sulfur heterocycles (thiacrown compounds) 10-15 by reactions with diiodomethane, 1,2-dibromoethane, and cis-1,2-dichloroethylene. Metal-catalyzed cross coupling reactions of 7 with Grignard reagents gave mono-and dialkylcycloheptatrienes and the reactions of 7 with copper bis-(trimethylsilyl)amide yielded l-alkyl-6-[bis(trimethylsilyl)amino]-l,3,5-cycloheptatrienes. An improved procedure for the preparation of 1 was also described.In connection with our study on bridged heterocyclic compounds,1 2"3 we required a general synthetic method of cycloheptatrienes having a variety of substituents at the 1-and 6-positions. Although some examples of 1,6-disubstituted cycloheptatrienes have been reported,4 no general synthetic method has been known. Recently Vogel and his co-workers reported a useful synthetic method of cycloheptatriene-1,6-dicarboxylic acid and its application to the preparation of some 1,6-disubstituted cycloheptatrienes,5 but this method is mostly restricted to the synthesis of carbon-substituted derivatives. We have found that the photoreaction of benzocyclopropene (1) with thiocyanogen or iodine gives 1,6-dithiocyanatoor l,6-diiodo-l,3,5-cycloheptatriene, respectively, in a good yield and these compounds can be converted into various kinds of 1,6-disubstituted cycloheptatrienes.6,7 Results and DiscussionSynthesis of 1,6-Dithiocyanato-and 1,6-Diiodocycloheptatrienes. If the activated "double bond" of benzocyclopropene (1) reacts with a reagent X2 in such a way as shown in eq 1, it would provide a very useful approach to 1,6-disubstituted cycloheptatrienes. A literature 1 2 survey suggests, however, that the reactions with electrophilic reagents X2 lead to the formation of a product of type 3 instead of 2.8 The only exception is the reaction 3

An efficient synthetic approach for the transition metal-free preparation of 2-bromo-3-(bromomethyl)naphthalene from naphthalene

“…However, synthetic chemistry has begun to give way to applied chemistry, and interest in compounds with high synthetic potential has decreased. Naphthocyclopropenes's chemistry is interesting chemistry for synthetic applications and may be useful in the synthesis of crucial skeletons to applied chemistry [25,26]. There are a limited number of studies on benzoor naphthocyclopropenes and its derivatives in the literature [25][26][27].…”

“…Naphthocyclopropenes's chemistry is interesting chemistry for synthetic applications and may be useful in the synthesis of crucial skeletons to applied chemistry [25,26]. There are a limited number of studies on benzoor naphthocyclopropenes and its derivatives in the literature [25][26][27]. The easy cleavage of the three-member benzocyclopropene ring by electrophiles such as bromine, iodine, HCl, and AgNO3 in the presence of ethanol and aniline previously reported, is of interest both in mechanism and synthesis [26].…”

Dilithium Tetrachlorocuprate(II)

“…14,22-24 In one report, one of two iodides was replaced using Li 2 CuCl 4 (eq 22). 23 An example using a 1,3-diene indicates that palladium catalysis may be more effective for these types of transformations (eq 23). There is one report in which a carbonylative cyclization was observed, presumably by intramolecular trapping of an acylmetal derivative (eq 24).…”

Synthese von Dimethyl‐4a,8a‐methanophthalazin‐1,4‐dicarboxylat und Derivaten

“…UVjVIS (CH2CI2): 268 (3,52). IR (KBr): 3320, 3060, 2990(KBr): 3320, 3060, , 2945(KBr): 3320, 3060, , 2900(KBr): 3320, 3060, , 2860(KBr): 3320, 3060, , 1750(KBr): 3320, 3060, , 1720(KBr): 3320, 3060, , 1610(KBr): 3320, 3060, , 1475 …”