89474-85-1Relevant articles and documents
A total synthesis of (+/-)-triophamine
Piers, Edward,Chong, Michael J.,Gustafson, Kirk,Andersen, Raymond J.
, p. 1 - 5 (2007/10/02)
Treatment of ethyl 2-pentynoate (14) with lithium(phenylthio)(tri-n-butylstannyl)cuprate (12) afforded, in 76 percent yield, ethyl (Z)-3-(tri-n-butylstannyl)-2-pentenoate (15).On the other hand, when compound 14 has allowed to react with the (tri-n-butylstannyl)copper reagent 13, ethyl (E)-3-(tri-n-buthylstannyl)-2-pentenoate (21) was produced in 83 percent yield.Reduction (diisobutylaluminum hydride, ether) of the esters 15 and 21 gave the alcohols 16 and 22, respectively.Treatment of each of the latter substances with pyridine -- sulfur trioxide complex, followed by further reduction of the resultant intermediates with lithium aluminum hydride, provided the geometrically isomeric alkenylstannanes 17 and 23.Conjugate addition of (E)-3-lithio-2-pentene (18) (formed by transmetalation of 17) to compound 19 produced the olefinic trimethylhydrazide 20, which was converted (diisobuthylaluminum hydride, ether; pyridinium dichromate, dimethylformamide) into the corresponding carboxylic acid 2.Subjection of compound 23 to a sequence of reactions identical with that used for the conversion of 17 into 2 provided the isomeric acid 3, which was identical (infrared, 1H nmr) with the natural acid derived from triophamine (1).Conversion of 3 into the p-nitrophenyl ester 26, followed by condensation of the latter substance with guanidine, afforded a chromatographically separable mixture of (+/-)-triophamine (1) and the corresponding diastereomer.
