Total Synthesis of Dihydroclerodin from (R)-(−)-Carvone
摘要:
The first total synthesis of the natural enantiomer of the insect-antifeedant dihydroclerodin (1) and lupulin C (40) has been achieved starting from (R)-(-)-carvone (2). In the applied strategy, the hexahydrofuro[2,3-b]furan moiety was introduced in an early stage of the synthesis. The correct configuration at C-9, C-11, C-13, and C-16 was established by application of a remarkably diastereoselective Mukaiyama reaction. The desired configuration at C-10 was obtained by catalytic reduction of the intermediate enone 21. After annulation of the second ring, the structural features at C-4, C-5, and C-6 were introduced. The successful finishing of the synthesis included a Chugaev elimination to give the exocyclic double bond at C-4 that is present in lupulin C. Oxidation of this double bond with m-CPBA afforded dihydroclerodin.
The Kharasch reaction revisited: CuX3Li2-catalyzed conjugate addition reactions of Grignard reagents
作者:Manfred T. Reetz、Alois Kindler
DOI:10.1016/0022-328x(95)05699-p
日期:1995.10
The conjugate addition of Grignardreagents RMgX to α,β-unsaturated ketones and esters is effectively catalyzed by soluble copper ate-complexes of the type CuX3Li2, e.g. CuI · 2LiCl. In the presence of Me3SiCl the corresponding ketone enolsilanes are formed in high yield and selectivity. Diasteroselectivity in the case of chiral ketones is similar to that observed by using stoichiometric amounts of
格氏试剂RMgX向α,β-不饱和酮和酯的共轭加成可通过CuX 3 Li 2类型的可溶性铜酸酯络合物(例如CuI·2LiCl )有效地催化。在Me 3 SiCl存在下,可以高产率和高选择性形成相应的酮烯醇硅烷。在手性酮的情况下,非对映选择性类似于通过使用化学计量的铜酸盐R 2 CuLi所观察到的非对映选择性。因此,CuX 3 Li 2催化的格氏试剂的1,4-加成可能是工业上可行的方法。
Synthesis of Novel Functionalized Polymers for the Diastereoselective Protonation of Chiral Enolates
Samarium(II) iodide promoted radical ring opening reactions of cyclopropyl ketones
作者:Robert A. Batey、William B. Motherwell
DOI:10.1016/0040-4039(91)80245-2
日期:1991.11
Radical ring opening reactions of cyclopropyl ketones mediated by samarium(II) iodide-induced single electron transfer have permitted the elaboration of a tandemrearrangementcyclisation strategy. The resultant samarium enolates may be effectively quenched on oxygen or carbon by electrophiles.
Enantioselective synthesis of highly functionalised cyclohexanones starting from R-(−)-carvone
作者:Tommi M. Meulemans、Gerrit A. Stork、Ben J.M. Jansen、Aede de Groot
DOI:10.1016/s0040-4039(98)01367-7
日期:1998.9
Copper (I) catalysed conjugateaddition of methylmagnesium iodide to R-(−)-carvone and trapping the enolate as its trimethylsilyl enol ether, followed by a trityl perchlorate (TrClO4) catalysed Mukaiyama-aldol reaction, is an efficient method for the preparation of highly functionalised cyclohexanones which can be used as starting compounds in the total syntheses of enantiomerically pure clerodanes