Fischer carbene complexes in heterocyclic synthesis.: Selective cycloaddition reactions to 2-aza-1,3-butadienes

被引:49
作者
Barluenga, J [1 ]
Tomás, M [1 ]
Ballesteros, A [1 ]
Santamaría, J [1 ]
Suárez-Sobrino, A [1 ]
机构
[1] Univ Oviedo, CSIC, Unidad Asociada, Inst Univ Quim Organomet Enrique Moles, E-33071 Oviedo, Spain
关键词
D O I
10.1021/jo9715074
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
A structurally diverse set of Fischer carbene complexes are reacted with substituted 3-[(trimethylsilyl)oxy]-2-aza-1,3-butadienes 1, yielding 5- to 7-membered nitrogen-containing heterocycles in a selective manner. Aryl and heteroarylmetal carbenes 2 undergo [4 + 1] cycloaddition with 1 leading to pyrrolidone derivatives 3-5 or 6-9, depending on the C1-substituent of 1. The [(trimethylsilyl)ethynyl]carbene 10a gives rise to metal-containing and metal-free [4 + 2] cycloadducts 11 and 12, respectively, whereas the (phenylethynyl)carbene 10b furnishes azafluorenones 13 by a tandem [4 + 2] cycloaddition/pentaannulation process. In the case of alkenyl carbene complexes 14 the regioselective [4 + 3] cycloaddition is the only observed transformation. Thus, their reaction with the phenyl-substituted azadiene 1d-resulted in the formation of a approximate to 1:1 mixture of diastereoisomers 15 and 16, whereas in the case of the tert-butyl-substituted azadiene Ic the cis-diastereoisomers 15 are selectively formed. This heptaannulation is proposed to occur by a cyclopropanation/aza-Cope rearrangement.
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页码:9229 / 9235
页数:7
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