Preparation of Dicarbonyl[hydrotris(1-pyrazolyl)borato](3-allyl)molybdenum Complexes Bearing Electron-Donating Substituents
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- 作者：Yancey D. Ward ; Lawrence A. Villanueva ; Gary D. Allred ; and Lanny S. Liebeskind
- 刊名：Organometallics
- 出版年：1996
- 出版时间：October 1, 1996
- 年：1996
- 卷：15
- 期：20
- 页码：4201 - 4210
- 全文大小：308K
- 年卷期：v.15,no.20(October 1, 1996)
- ISSN：1520-6041
文摘
Cyclic and acyclicdicarbonyl[hydrotris(1-pyrazolyl)borato][
3-1-((tert-butyldimethylsilyl)oxy)allyl]molybdenum complexes and a variety of their 1-acetoxyand 1-alkoxy (RO = MeO,i-PrO) analogues were prepared and characterized by IR and1H and 13C NMR spectroscopyand, in the case of[TpMo(CO)2[-(1,2,3)-(±)-(1R,2S,3S)-1-methoxy-2-cyclohexen-1-yl],byX-ray crystallography. These complexes were prepared in moderateto excellent yields bythe tert-butyldimethylsilyl chloride promoted oxidativeaddition of 
,
-unsaturated aldehydesand acyclic and cyclic ketones to(DMF)3Mo(CO)3 followed by ligandmetathesis withpotassium hydrotris(1-pyrazolyl)borate. The1-tert-butyldimethylsiloxy- and the 1-methoxy-and 1-isopropoxy-substituted acyclic complexes were formed solely asthe syn isomer;however, the 1-acetoxy analogue underwent isomerization to athermodynamic mixture ofthe syn and anti isomers in which theanti isomer predominated (3.7 : 1). The1-((tert-butyldimethylsilyl)oxy)-3-alkyl- or 1-alkoxy-3-alkyl-disubstitutedacyclic complexes wereformed with syn-silyloxy/anti-alkyl orsyn-alkoxy/anti-alkyl stereochemistry, whilethedisubstituted allyls bearing a 1-acetoxy substituent existed asmixtures of both possible syn/anti isomers and the syn/syn and anti/antiisomers. The conformation and configurationof the isomers was confirmed through nOe studies on several complexesand by X-raycrystallography in the case of[TpMo(CO)2[-(1,2,3)-(±)-(1R,2S,3S)-1-methoxy-2-cyclohexen-1-yl].
3-1-((tert-butyldimethylsilyl)oxy)allyl]molybdenum complexes and a variety of their 1-acetoxyand 1-alkoxy (RO = MeO,i-PrO) analogues were prepared and characterized by IR and1H and 13C NMR spectroscopyand, in the case of[TpMo(CO)2[-(1,2,3)-(±)-(1R,2S,3S)-1-methoxy-2-cyclohexen-1-yl],byX-ray crystallography. These complexes were prepared in moderateto excellent yields bythe tert-butyldimethylsilyl chloride promoted oxidativeaddition of ,-unsaturated aldehydesand acyclic and cyclic ketones to(DMF)3Mo(CO)3 followed by ligandmetathesis withpotassium hydrotris(1-pyrazolyl)borate. The1-tert-butyldimethylsiloxy- and the 1-methoxy-and 1-isopropoxy-substituted acyclic complexes were formed solely asthe syn isomer;however, the 1-acetoxy analogue underwent isomerization to athermodynamic mixture ofthe syn and anti isomers in which theanti isomer predominated (3.7 : 1). The1-((tert-butyldimethylsilyl)oxy)-3-alkyl- or 1-alkoxy-3-alkyl-disubstitutedacyclic complexes wereformed with syn-silyloxy/anti-alkyl orsyn-alkoxy/anti-alkyl stereochemistry, whilethedisubstituted allyls bearing a 1-acetoxy substituent existed asmixtures of both possible syn/anti isomers and the syn/syn and anti/antiisomers. The conformation and configurationof the isomers was confirmed through nOe studies on several complexesand by X-raycrystallography in the case of[TpMo(CO)2[-(1,2,3)-(±)-(1R,2S,3S)-1-methoxy-2-cyclohexen-1-yl].