Rhenium-Catalyzed 1,3-Isomerization of Allylic Alcohols: Scope and Chirality Transfer
作者:Christie Morrill、Gregory L. Beutner、Robert H. Grubbs
DOI:10.1021/jo061436l
日期:2006.9.1
The scope of the triphenylsilyl perrhennate (O3ReOSiPh3, 1) catalyzed 1,3-isomerization of allylicalcohols has been thoroughly explored. It was found to be effective for a wide variety of secondary and tertiary allylicalcohol substrates bearing aryl, alkyl, and cyano substituents. Two general reaction types were found which gave high levels of product selectivity: those driven by formation of an
Exploring the versatility of the Johnson–Claisen rearrangement: access to functionally versatile δ-ethoxycarbonyl-α,β-unsaturated nitriles
作者:Kelly L. Cosgrove、Ross P. McGeary
DOI:10.1016/j.tet.2010.02.045
日期:2010.4
aldehydes were converted to cyanohydrins, by employing either KCN in aqueous acid, or by using TMSCN with catalytic K2CO3, followed by acid hydrolysis of the TMS ether. These cyanohydrins underwent a Claisenrearrangement employing a modified Johnson–Claisen protocol to yield unsaturated nitriles in good yields and with moderate E/Z selectivity.
描述了实际进入δ-乙氧基羰基-α,β-不饱和腈的方法。通过在酸性水溶液中使用KCN或通过将TMSCN与催化性K 2 CO 3一起使用,然后将TMS醚酸水解,可以将α,β-不饱和醛转化为氰醇。这些氰醇经过改良的Johnson-Claisen方案进行了Claisen重排,以高收率和适度的E / Z选择性产生不饱和腈。
An Efficient and Solvent-Free
Synthesis of Mixed Ortho Esters
作者:Ross McGeary、Kelly Cosgrove
DOI:10.1055/s-2008-1078215
日期:——
Primary, secondary and electron-deficient tertiary alcohols react rapidly with ketene dimethyl acetal to form mixed ortho esters, without catalysts and under solvent-free conditions. 1,2-Diols yield bis(mixed ortho esters), rather than cyclic ortho esters.
A New Strategy for Construction of Eight-Membered Carbocycles by Brook Rearrangement Mediated [6 + 2] Annulation
作者:Kei Takeda、Hidekazu Haraguchi、Yasushi Okamoto
DOI:10.1021/ol0353767
日期:2003.10.1
text] A newly developed strategy for construction of eight-memberedcarbocycles via [6 + 2] annulation that involves the combination of beta-alkenoyl acylsilanes and a vinyllithium derivative is described. A unique feature of this annulative approach is that it enables in one operation and a stereoselective manner construction of eight-membered ring systems containing useful functionalities for further