described, starting from optically pure (S)-malic acid and methyl (R)-3-hydroxy-2-methylpropionate. The synthesis is highly convergent by coupling the three fragments C1-C6 (fragment D), C7-C10 (fragment C), and C11-C21 (fragment B). Key steps are two stereoselectiveWittig type olefinations to generate the 12,13- and 16,17-double bonds, an enantioselective Mukaiyama aldol addition to synthesize fragment
An efficient N-centred radical 5-exo cyclization/addition/aromatization cascade by cooperative visible light photoredox and cobalt catalysis is described, giving dihydropyrazole-fused benzosultams in satisfactory yields.
Improved synthesis of β,X-unsaturated ketones by the reaction of allylic zinc bromides with nitriles.
作者:G. Rousseau、J.M. Conia
DOI:10.1016/s0040-4039(01)92513-4
日期:1981.1
The reaction of allylic bromides with nitriles in the presence of ZnAg couple leads, after hydrolysis, to β,X-unsaturated ketones in high yield.
ZnAg对存在下,烯丙基溴与腈的反应在水解后以高收率生成β,X-不饱和酮。
Synthesis of the C(1)-C(9) segment of the cytotoxic macrolides epothilon A and B
作者:Johann Mulzer、Andreas Mantoulidis
DOI:10.1016/s0040-4039(96)02156-9
日期:1996.12
The C(1)-C(9) segment 3 of the macrolides epothilon A and B1, two new cytotoxic natural products, has been synthesized in a direct manner. Key steps in the synthesis are a stereoselective aldol reaction of 6 and 7 and a Brown allylation of 9.
applied for the first time to the direct conversion of N−H and O−H bonds into N‐ and O‐centred radicals, enabling a general and selective oxidative radical oxyamination and dioxygenation of various β,γ‐unsaturated hydrazones and oximes. In the reaction, O2 was employed not only as a terminal oxidant but also as the oxygen source. This protocol provided efficient access to the synthesis of various synthetically