The reaction of tert-butylalkynyl chromium Fischercarbenecomplex 1 with nitrones 2 affords β-enamino-ketoaldehydes 4 by the light-promoted rearrangement of the corresponding [3+2] cycloadduct carbenecomplexes3. On the other hand, [3+2] cycloaddition of chiral nonracemic Fischeralkenylcarbenecomplexes 19 with nitrilimines 10 yields enantiomerically pure Δ2-pyrazolines with high regio- and diastereoselectivity
Ten 2,3-disubstituted 4-phenylsulfonyl isoxazolidines (3a-j) were prepared by 1,3-dipolar cycloaddition reaction of substituted nitrones (1a-j) with phenyl vinyl sulfone (2). The reaction products were identified by means of IR, NMR, and MS data. In addition, the factors influencing on the electron ionization induced mass spectral fragmentation of the title products are discussed in detail.
The stereoselective synthesis of novel spiro-oxazinanone nucleosides 9 and 10 has been achieved by microwave assisted 1,3-dipolar cycloaddition of exo-glucal (1) and nitrones (2), and followed by reduction, stereospecific recyclization, and catalytic deprotection. The structures of the spironucleosides were determined according to the H-1 NMR, C-13 NMR, 2D NMR, MS, and X-ray analyses, and the biological activities of the title compounds against glycosidases (alpha-amylase, alpha-glucosidase, and beta-glucosidase) and cytotoxicity were also evaluated. (C) 2008 Elsevier Ltd. All rights reserved.
STAMM H.; STEUDLE H., TETRAHEDRON, 1979, 35, NO 5, 647-650
作者:STAMM H.、 STEUDLE H.
DOI:——
日期:——
HWU, JIH RU;ROBL, JEFFREY A.;WANG, NAELONG;ANDERSON, DENISE A.;KU, JAMES;+, J. CHEM. SOC. PERKIN TRANS. PT 1,(1989) N0, C. 1823-1831
作者:HWU, JIH RU、ROBL, JEFFREY A.、WANG, NAELONG、ANDERSON, DENISE A.、KU, JAMES、+