Reduction asymetric

For sodium cyanoborohydride — hydrogen chloride reagent the direction of the reductive opening of the dioxolane acetals obeys the same rule, it depends on the stereochemistry at the asymetric, benzylidene acetal carbon [168, 169]. Methyl exo-2,3 4,6-di-0-benzylidene-a-D-mannopyranoside is cleaved in oxolane solution to give 50 % of the 3,6-di-O-benzyl derivative, which is also the major product in the reaction of methyl 3-0-benzyl-4,6-0-benzylidene-a-D-mannopyranoside. The 2-O-benzyl isomer (20) was cleaved nonselectively, indicating again the effect of the bulk of the C-3 substituent [169]. A compatibility of this reagent, as well as of borane — tri-... 

Acetylenes, homologation to allenes, 63, 203 Acetylenes, in peptide synthesis, 63, 175 a,B-ACETYLENIC KETONES, ASYMETRIC REDUCTION OF, 63, 57 ACID CHLORIDES FROM a-KETO ACIDS, 61, 1 Acrolein [107-02-8], 62, 140... 

The conversion of prochiral centres in cyclic intermediates into fully blown chiral centres is a profitable way to transmit stereochemical information. The ant trail pheromone monomorine 42 when re-drawn so that we can see all three hydrogen atoms on the same surface of the molecule 42a, is an ideal candidate for synthesis by reductive animation. One of the three centres must be made asymetrically and then the other two set up by reduction of imines formed from that amine and two ketones as in 43. 

The position in binding energy and the asymetric shape of the Ir 4f 7/2 peak indicate the presence of Ir species. Moreover one notices that some amount of chlorine remained into the catalyst after the reduction treatment. 

ASYMETRIC REDUCTION (-)-N-Dodecyl-N-methyiephediinium bromide. Lithium... 

---