Borane and alane reductions of bulky N,N′-diaryl-1,3-diimines:: structural characterization of products and intermediates in the diastereoselective synthesis of 1,3-diamines

被引:19
|
作者
Carey, DT [1 ]
Mair, FS [1 ]
Pritchard, RG [1 ]
Warren, JE [1 ]
Woods, RJ [1 ]
机构
[1] UMIST, Dept Chem, Manchester M60 1QD, Lancs, England
关键词
D O I
10.1039/b306401h
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Two new C-2-symmetric diazaborinanes were prepared by diastereoselective intramolecular dihydroboration of bulky 1,3-diamines, the remarkably stable l-[HB(2,6-Pr-2(i)-C6H3NCHMe)(2)CMe2], from which it was not possible to isolate free diimine, and the less bulky l-[HB(2-Pr-i-C6H4NCHMe)(2)CMe2], which yielded l-(2-Pr-i-C6H4NHCHMe)(2)CMe2 on acid work up. The BH3 reductions were highly diastereoselective for l-products (de > 95%). Use of AlCl3/LiAlH4 mixtures in diethyl ether gave lower (de approximate to 75%) and opposite selectivity, yielding predominantly u-(2,6-Pr-2(i)-C6H3NHCHMe)(2)CMe2 upon work up, via au-[H2Al(2,6-Pr-2(i)-C6H3)NHCHMeCMe2CHMeN(2,6-Pr-2(i)-C6H3)] intermediate in a two-step reduction. All products were characterized crystallographically.
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页码:3792 / 3798
页数:7
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