Trifluoromethanesulfonic (triflic) acid catalyzed transformations of .alpha.-hydroxy carbonyl compounds
摘要:
Triflic acid catalyzed reaction of 2-hydroxy-2-adamantanecarboxylic acid results via ionizative decarbonylation in the formation of adamantonone. Under carbon monoxide pressure pinacol-type rearrangement gives 4,5-homoadamantanedione. Reaction of a series of alpha-hydroxy ketones result in fragmentation, deprotonation, and cyclization, respectively. The reactions and their suggested mechanism are discussed.
KOENIGKRAMER R. E.; ZIMMER H., TETRAHEDRON LETT., 1980, 21, NO 11, 1017-1020
作者:KOENIGKRAMER R. E.、 ZIMMER H.
DOI:——
日期:——
OLAH, GEORGE A.;WU, AN-HSIANG, J. ORG. CHEM., 56,(1991) N, C. 2531-2534
作者:OLAH, GEORGE A.、WU, AN-HSIANG
DOI:——
日期:——
HUENIG S.; WEHNER G., SYNTHESIS <SYNT-BF>, 1975, NO 6, 391-392
作者:HUENIG S.、 WEHNER G.
DOI:——
日期:——
The reduction of α-silyloxy ketones using phenyldimethylsilyllithium
作者:Ian Fleming、Richard S. Roberts、Stephen C. Smith
DOI:10.1039/a709114a
日期:——
diol PhCH(OH)CH(OH)Ph 39. The reaction between phenyldimethylsilyllithium and the acyloin silyl ether 8d (R = But) does not give the ketone ButCH2COBut, but gives instead the anti-Felkin meso diol ButCHOHCHOHBut 40 also with high selectivity (Scheme 12). Silyllithium and some related reagents react with trifluoromethylketones 46 and 48 to give α,α-difluoro silyl enol ethers 47 and 49 (Scheme 14).
苯基二甲基甲硅烷基锂与酰氯甲硅烷基甲醚RCH(OSiMe 3)COR 8反应生成区域定义的甲硅烷基烯醇醚RCH C(OSiMe 2 Ph)R 9,并因此通过水解酮RCH 2 COR 10产生。收率可能很高,但通常是中等水平。建立这种减少的机制涉及布鲁克重排(方案6)而不是彼得森消除(方案1)。尽管在每种情况下机理似乎都是相同的,但甲硅烷基烯醇醚9的立体化学在芳族系列(R = Ph,方案7)和脂族系列(R =环己基,方案8)中在意义上是相反的,主要的芳族甲硅烷基烯醇醚是热力学上较不稳定的异构体E -PhCH C(OSiMe 2Ph)Ph E -9aa和主要的脂族甲硅烷基烯醇醚是热力学更稳定的异构体Z -cC 6 H 11 CH C(OSiMe 2 Ph)-cC 6 H 11 Z -9ba。这是芳族系列中反反费尔金攻击的结果。与甲硅烷基的反应醚卜吨CH(OSiMe 3)COPH图13b是在给予正常Ž