engleski

Reactions of 3-ethyl- and 3-phenyl-1-azabicyclo[1.1.0]butanes with tosyl chloride and tosyl azide

Reactions of 3-ethyl-1-azabicyclo[1.1.0]butane (4) with TsCl and with TsN3 have been studied in aqueous THF solution and in the presence of a variety of nucleophilic trapping agents. Thus, reaction of 4 with TsCl-Na2CO3 afforded N-p-toluenesulfonyl -3-chloro-3-ethylazetidine (6, 34%), N-(N'-p-toluenesulfonyl-3'-ethyl-3'-azetidinyl)-3-chloro-3-ethylazetidine (7, 3.4%), and N-p-toluenesulfonyl-3-ethyl-3-hydroxyazetidine (8, 31%). When this reaction was repeated in the presence of a tenfold molar excess of NaCl, the yield of 6 inceased to 80%, primarily at the expense of 8, which was isolated in only 4.3% yield. When this reaction was performed in the presence of a tenfold molar excess of NaN3, the predominant reaction products were TsN3 (32%) and an inseparable mixture of 6 and N-p-toluenesulfonyl-3-azido-3-ethylazetidine (9 ; product ratio 6:9 = 1:1). Finally, 4 reacted with TsN3 under four different sets of reaction conditions. In every case, 9 was the major product isolated from these reactions (32-74%). Similar results were obtained for the corresponding reactions of 3-phenyl-1-azabicyclo[1.1.0]butane (1) with TsCl. All of the results reported herein are consistent with expectations based upon a mechanism that involves nucleophilic trapping of a putative tertiary carbocationic intermediate.

Azabicyclobutane

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