Organometallics p. 2571 - 2580 (1997)
Update date:2022-08-03
Topics:
Aumann, Rudolf
Fr?hlich, Roland
Zippel, Frank
Addition of alkenyl N-H. imidates RCH=CR1C(OEt)=NH (8a-d; R, R1 = Ph, Me, H) to (1-alkynyl)carbene complexes (CO)5M=C(OEt)C≡CPh (6a,b; M = Cr, W) affords novel 5-aza-1-metalla-l,3,5,7-octatetraenes(CO) 5M=C(OEt)CH=C(Ph)N=C(OEt)CR1=CHR((Z)-9a-h; by Michael addition) together with 2,5-diethoxy-2H-pyrrole complexes 10a-h (by 3 + 2 cycloaddition) as well as 2,4-diethoxy-2H-dihydroazete complexes 11e-h (by 2 + 2 cycloaddition) in good overall yields. The product ratio 9:10:11 is strongly influenced by the nature of the metal (chromium or tungsten). Thus, formation of 5-aza-1-metalla-l,3,5,7-octatetraenes 9 is favored in the case of M = W, while 2H-dihydroazete complexes 11 are major products in the case of M = Cr. Compounds 9a-d undergo smooth cyclization at 80-90 °C to give 2,3-diethoxy-2H-pyrrole complexes 12a-d (which are regioisomers of 10a-d) in 86-93% yields, from which (metal-free) 2H-pyrroles 13a-d are generated on thermolysis at 110 °C. X-ray structure analyses are reported for the 5-aza-1-metalla-1,3,5,7-octatetraene 9b, the (regioisomeric) 2H-pyrrole complexes 10b and 12b, and the 2H-dihydroazete complex 11e.
View MoreChengdu Chengnuo New-Tech Co., Ltd
Contact:0086-028-85749078
Address:4 Jiuyang road,Jiulong industrial port,Chengdu, China
Tianjin Tongde Biological Technology Co., Ltd.
Contact:86-22-23309138
Address:Room 402, bulidingE3 Detection certification park, XiQingDistrict, Tianjin City
ANHUI CHEM-BRIGHT BIOENGINEERING CO.,LTD
Contact:86-561-4080321
Address:No.8 Lieshan Industrial Zone of Huaibei
Contact:
Address:308# dongwu avenue dongxihu district wuhan city
Chengdu King-tiger Pharm-chem. Tech. Co., Ltd
Contact:028-85317716
Address:Tianfu Life Science Park, No. 88 South Keyuan Road, Gaoxin District, Chengdu City, Sichuan Province, PRC.
Doi:10.1016/j.bmcl.2011.02.048
(2011)Doi:10.1016/j.tet.2011.03.005
(2011)Doi:10.1055/s-1990-26970
(1990)Doi:10.1016/S0040-4039(00)97413-6
(1990)Doi:10.1016/j.tet.2011.02.069
(2011)Doi:10.1016/0031-9422(90)87076-7
(1990)