Synthesis of Pyrroles from 1-Dialkylamino-3-phosphoryl(or phosphanyl)allenes through 1,5-Cyclization of Conjugated Azomethine Ylide Intermediates
作者:Martin Reisser、Gerhard Maas
DOI:10.1021/jo049586o
日期:2004.7.1
5-diarylpyrroles 6a−f and [a]-annulated benzo[c]azepines 7a,b,d. These transformations are likely to include conjugated azomethine ylide intermediates that can undergo either a 1,5- or a 1,7-electrocyclization. The periselectivity is markedly shifted toward 1,5-cyclization when the diphenylphosphanyl substituent is replaced by the diphenylphosphoryl group. Thus, 1-dialkylamino-3-(diphenylphosphoryl)allenes
Propyne Iminium Salts and Phosphorus(III) Nucleophiles: Synthesis of (3-Morpholinoallenyl)phosphanes and -phosphane Oxides or 1-(Morpholinopropargyl)phosphanes and -phosphonates
作者:Martin Reisser、Alexandra Maier、Gerhard Maas
DOI:10.1002/ejoc.200300080
日期:2003.6
Treatment of 4-(1,3-diphenyl-l-propynylidene)morpholinium triflate (1a) with the neutralphosphorusnucleophiles Me3Si−PPh2, Me3Si−P(Ph)C5H11, and Me3SiO−PPh2 affords (3-morpholinoallenyl)phosphanes 4 and 5 and (3-morpholinoallenyl)phosphane oxide 11, respectively. In contrast to these conjugate addition reactions at the ambident propyne iminium moiety of 1a, nucleophilic attack by Me3Si−PEt2 and Me3SiO−P(OEt)2