Ultrasound-promoted synthesis of novel dispirocyclic frameworks from aza-Claisen rearrangements of Baylis-Hillman amines.
A novel tetracyclic frameworks of dispiropyrrolizidines can be obtained in moderate to good yields via the 1,3-dipolar cycloaddition of azomethine ylides with dipolarophiles derived from aza-Claisen rearrangement of Baylis-Hillman amines. The transformations are highly regioselective and stereoselective, affording the desired compounds in reduced time and increased yields under ultrasound irradiation at room temperature. All the products are confirmed by 1H, 13C NMR, IR and MS spectra, while their molecular structures are elucidated by X-ray crystallography of a selected sample.
Ge
Shao-Qin
SQ
Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, P.R. China.
Hua
Yun-Yu
YY
Xia
Min
M
D000588:Amines / Q000737:chemistry* / Q000528:radiation effects*; D001372:Aza Compounds / Q000737:chemistry* / Q000528:radiation effects*; D003500:Cyclization; D007202:Indicators and Reagents; D007510:Isatin / Q000737:chemistry; D008958:Models, Molecular; D011392:Proline / Q000737:chemistry; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis* / Q000528:radiation effects; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000528:radiation effects; D014465:Ultrasonics; D014961:X-Ray Diffraction
D000588:Amines; D001372:Aza Compounds; D007202:Indicators and Reagents; D011763:Pyrrolizidine Alkaloids; D013141:Spiro Compounds; D007510:Isatin; D011392:Proline