نتایج جستجو برای: silyl ethers

تعداد نتایج: 8150  

Journal: :Chemical communications 2013
Lu Gao Ji Lu Zhenlei Song Xinglong Lin Yongjin Xu Zhiping Yin

An unusual [1,5]-Brook rearrangement of the lithium alkoxide of geminal bis(silyl) homoallylic alcohol is described. The unique steric and electronic effects of geminal bis(silane) were found to be crucial for promoting this long-range silyl migration, as well as for facilitating the subsequent γ/Z-selective addition of silyl allyllithium with carbonyl compounds to synthesize diverse configurat...

Journal: :Chemical communications 2013
Yingle Liu Jiawang Liu Yangen Huang Feng-Ling Qing

A tunable and highly regio- and diastereoselective addition of acyclic silyl dienolates 2 to several α-fluoroalkyl sulfinylimines 1 was developed. By appropriate choice of the Lewis acid catalyst, two new chiral α-fluoroalkyl amines 3 and 4 were obtained in good yields and excellent diastereoselectivities (up to >99 : 1 dr), respectively.

1996
Shinji Marumoto Hiroshi Kogen Shunji Naruto

The stereoselective aldol reaction represents one of the major challenges of modern synthetic organic chemistry.1 Many useful methodologies have been reported during the last few decades. For instance, 1,2-asymmetric induction in the aldol reaction of a-alkoxy aldehydes with silyl enol ethers or ketene silyl acetals is well-established.2 The aldol reaction between a-alkoxy aldehydes and a malon...

Journal: :Bioconjugate chemistry 2002
Paul O Zamora Ray Tsang Louis A Peña Shigemasa Osaki Prantika Som

A growth factor delivery system was developed that is based on the use of silyl-heparin, a chemically modified analogue of heparin. The silyl-heparin was adsorbed onto surfaces by hydrophobic interaction via the prosthetic unit and can then be used as a solid-phase adsorbent for bFGF. All the coating steps were performed by adsorption, a process that allowed preparation of surfaces by immersion...

Journal: :Journal of the American Chemical Society 2007
David A Evans Yimon Aye

The current realm of Lewis acid-promoted propargylsilane additions to carbonyl groups2 may be subdivided into two mechanistically distinct categories: (i) additions proceeding via a desilylation pathway;3 (ii) additions involving a [1,2]-silyl shift.4 Process (i) generates allenic alcohols and is most common when nonbulky silyl groups such as TMS are employed,3 whereas the latter scenario has b...

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