The allylic substitution of secondary allylic picolinates and copper reagents for the construction of a quaternary carbon was applied to synthesis of sporochnol. The enantiomerically enriched allylic picolinate (R)-5 was synthesized through the asymmetric hydrogen transfer of acetylene ketone 11 and the Pd-catalyzed methylation of the iodoallylic alcohol 16a. The key allylic substitution of the allylic picolinate (R)-5 with 4-MeOC6H4MgBr/Cu(acac)(2) (2:1) proceeded with 95% chirality transfer with 98% regioselectivity to afford anti S(N)2' product 6 in 89% yield, which was converted to the methyl ether of unnatural (R)-sporochnol. Similarly, the methyl ether of (S)-sporochnol (the natural form) was synthesized.
A synthesis of allylic alcohols from β-γ-epoxysulfones
作者:Philip J. Kocienski
DOI:10.1016/s0040-4039(01)93527-0
日期:1979.1
[EN] BIODEGRADABLE LIPIDS FOR THE DELIVERY OF ACTIVE AGENTS<br/>[FR] LIPIDES BIODÉGRADABLES POUR L'ADMINISTRATION D'AGENTS ACTIFS
申请人:ALNYLAM PHARMACEUTICALS INC
公开号:WO2013086354A1
公开(公告)日:2013-06-13
The present invention relates to a cationic lipid having one or more biodegradable groups located in a lipidic moiety (e.g., a hydrophobic chain) of the cationic lipid. These cationic lipids may be incorporated into a lipid particle for delivering an active agent, such as a nucleic acid. The invention also relates to lipid particles comprising a neutral lipid, a lipid capable of reducing aggregation, a cationic lipid of the present invention, and optionally, a sterol. The lipid particle may further include a therapeutic agent such as a nucleic acid.
Generation of Hafnium Hydride
and its Application to Chemo- and Diastereoselective Reactions
作者:Ikuya Shibata、Shinji Miyamoto、Toru Itoh、Akio Baba
DOI:10.1055/s-0029-1216739
日期:——
Hafnium hydride was generated by the transmetalation between Bu3SnH and HfCl4 using either THF or EtCN as the solvent. This process effectively reduced aldehydes, aldimines, ketones, and esters. In the hafnium hydride reduction of α-alkoxy-ketones, the diastereoselectivity was dependent on whether THF or EtCN was used as the solvent.