Total Synthesis of Sarcophytol A, an Anticarcinogenic Marine Cembranoid
摘要:
A highly stereo- and enantioselective total synthesis of sarcophytol A (1), a marine cembranoid promising as a cancer chemopreventive agent, is described. The nitrile 10 obtained Z-selectively (Z:E = >35:1) by the Horner-Emmons reaction of (E,E)-farnesal (5) with the phosphononitrile 9 in 91% yield was converted to the conjugated 2(Z),4(E)-dienal 3 in which the terminal (E)-methyl group was functionalized. Intramolecular alkylation of the cyanohydrin TMS ether of 3 provided the macrocyclic ketone 2 in 79% of overall yield from 3 without isolation of the cyclic cyanohydrin 20 as well as its TMS ether 19. Reduction of 2 with several chiral LiAlH4 reagents afforded 1 highly enantioselectively (87-93% ee) in 78-97% yield, from which enantiomerically pure 1 (>99% ee) was readily obtained upon a single recrystallization.
Synthesis and stereochemistry of sarcophytol B: An anticancer cembranoid
作者:John E. McMurry、Joseph G. Rico、You-nan Shih
DOI:10.1016/s0040-4039(00)72708-0
日期:1989.1
A short (5 step), efficient synthesis of sarcophytol B (1) from farnesal is reported using a low-temperature, titanium-inducedpinacolcoupling reaction of 1,14-dialdehyde5 as the key step. An X-ray structure determination showed that sarcophytol B has trans diol stereochemistry.
Z-selective formation of trisubstituted α,β-unsaturated nitrile by the Horner-Emmons reaction
作者:Hisao Takayanagi
DOI:10.1016/s0040-4039(00)76763-3
日期:1994.3
Conditions which allow the Horner-Emmons reaction of phosphononitrile to proceed Z-selectively were clarified. The generality and usefulness of the procedure were demonstrated by an application to a stereoselective synthesis of plaunotol (9).