Alcohols synthesis, asym

In two studies toward the total synthesis of natural products it could be shown that the a,jS-unsaturated esters derived from the vinylogous Mukaiyama aldol reactions can be further functionalized into advanced intermediates. The C1-C7 segment of oleandolide commences with the VMAR of aldehyde 68 derived from the Roche ester. The so-generated stereo-triad was protected as PMB ether and the ester 76 was reduced to the allylic alcohol. Sharpless asym-... 

Organolithium compds.jchiral diamines Sec. alcohols from aldehydes Asym. synthesis... 

Synthesis of sec. alcohols from acylsilanes via 1,1-hydroxysilanes Asym. induction... 

A cold soln. of 2-oxobutyric acid in ethanol treated with L-(—)-a-methylhenzyl-amine in the same solvent, 10%-Pd-on-charcoal added, hydrogenated 10 hrs. at 30 /50 p.s.i. until 1 mole of has been absorbed, the catalyst removed by filtration, the filtrate coned., aq. 30%-alcohol and palladium hydroxide-on-charcoal added, then hydrogenated at 25 /50 p.s.i. until Hg-uptake ceases L-butyrine. Y 75.9-84.9% excess of enantiomorph 81.4%.— Debenzylation with other catalysts was not successful. Asym. induction occurs during reduction of the azomethine and debenzylation can be performed with little or no loss of configurational integrity. The configuration of the amino acids is the same as that of the a-methylbenzylamine from which it is derived. The magnitude of the induced asymmetry depends on the substrate and the catalyst. F. e. s. R. G. Hiskey and R. G. Northrop, Am. Soc. 83 4798 (1961) asym. synthesis of amino acids s. a. J. G. Sheehan and R. E. Chandler, Am. Soc. 83, 4795 (1961). 

Asym. diene synthesis Reversal of stereospecificity Alcohols from carboxylic acid esters... 

Sodium tetrahydridoborateiboron fluoride Asym. synthesis of alcohols... 

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