Enantioselective Construction of Cyclic Ethers by An Aldol-Cyclization Sequence
作者:Paul Galatsis、Scott D. Millan、George Ferguson
DOI:10.1021/jo961904z
日期:1997.7.1
We have modified the substrate used in deconjugative aldol-cyclizations by incorporating the Evans chiral auxiliary. The deconjugative aldol step, using boron enolates, gave the expected products with complete syn-aldol stereochemistry. These compounds could then undergo an iodine-mediated cyclization to form optically active products. Oxetanes and fused ring tetrahydrofurans were easily assembled with a variety of substitution patterns and with excellent enantiocontrol. The deconjugation of acyclic chiral enimides resulted in the loss of control of olefin geometry. However, these compounds did appear to cyclize with excellent enantiocontrol.
Aldol addition reactions of chiral crotonate imides
作者:David A. Evans、Eric B. Sjogren、Javier Bartroli、Robert L. Dow
DOI:10.1016/s0040-4039(00)85106-0
日期:1986.1
EVANS D. A.; SJOGREN E. B.; BARTROLI J.; DOW R. L., TETRAHEDRON LETT., 27,(1986) N 41, 4957-4960
作者:EVANS D. A.、 SJOGREN E. B.、 BARTROLI J.、 DOW R. L.
DOI:——
日期:——
Studies on the Synthesis of Bafilomycin A<sub>1</sub>: Stereochemical Aspects of the Fragment Assembly Aldol Reaction for Construction of the C(13)−C(25) Segment
作者:William R. Roush、Thomas D. Bannister、Michael D. Wendt、Jill A. Jablonowski、Karl A. Scheidt
DOI:10.1021/jo016413f
日期:2002.6.1
lithium enolate aldolreaction. In contrast, the aldolreaction of 6a and the chlorotitanium enolates of 7a,c were much less sensitive to the nature of the C(15)-hydroxyl protectinggroup. Studies of the reactions of chiral aldehydes with Takai's (gamma-methoxyallyl)chromium reagent 40 are also described. The stereoselectivity of these reactions is also highly dependent on the protectinggroups and stereochemistry