共 117 条
Synthesis of fused piperidinones through a radical-ionic cascade
被引:28
作者:
Godineau, Edouard
[1
]
Schenk, Kurt
[2
]
Landais, Yannick
[1
]
机构:
[1] Univ Bordeaux 1, Inst Mol Sci, CNRS, UMR 5255, F-33405 Talence, France
[2] Univ Lausanne, Inst Cristallog, BCP, CH-1015 Dorigny, Switzerland
关键词:
D O I:
10.1021/jo801308j
中图分类号:
O62 [有机化学];
学科分类号:
070303 ;
081704 ;
摘要:
Azabicyclo[4.3.0]nonanes were assembled, from chiral allylsilanes possessing an oxime moiety, using a stereocontrolled formal [2 + 2 + 2] radical-ionic process. The cascade involves the addition of an alpha-iodoester to the less substituted end of the enoxime which is then followed by a 5-exo-trig cyclization onto the aldoxime function, producing an alkoxyaminyl radical species which finally lactamizes to afford the titled piperidinone. High levels of stereoinduction were observed, demonstrating the ability of a silicon group located at the allylic position to efficiently control the stereochemistry of the two newly created stereogenic centers. When the radical cascade was extended to ketoximes, the resulting sterically hindered alkoxyaminyl radical did not react further with the initiator Et3B to produce the expected nucleophilic amidoborane complex. In sharp contrast, this long-lived radical recombined with the initial alpha-stabilized ester radical to produce a cyclopentane incorporating two ester fragments.
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页码:6983 / 6993
页数:11
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