Synthesis of three stereoisomeric forms of 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, the main component of the cephalic secretion of andrena wilkella

Yeast‐Mediated Stereoselective Synthesis

“…19) has also been studied [119,193,250,[260][261][262][263][264][265][266]. The yields for this reduction were between 30 and 80%, and the ee ranged between 77 and >98%.…”

Synthesis of Pheromones

“…Reduction of ethyl acetoacetate (A) with fermenting baker's yeast gives (S )-B. Synthesis of (2S,6R,8S )-88 was executed as a part of this project (Figure 4.35). 64,65 The hydroxy ester (S )-B (92% ee) was converted to iodide (S )-C (4 steps). Inversion of the configuration of (S )-B to (R)-D was possible by means of Mitsunobu inversion, which was further converted to (R)-C. Accordingly, both the enantiomers of C were prepared from the single enantiomer (S )-B. Alkylation of the dianion of methyl acetoacetate with (S )-C gave E, whose further alkylation with (S )-C afforded F. Successive treatments of F with base followed by acid effected hydrolysis, decarboxylation and acetalization to give ( 3 ± 0.7 (pentane) and +44.6 ± 0.7 (pentane), respectively.…”

Synthesis and Stereochemistry of Insect Derived Spiroacetals with Branched Carbon Skeletons

“…In addition, structures 64 and 65 were acquired in another way, with more stereochemical control, by ADtechnology, and this is described later in Scheme 8. Alkene 72 was deprotected, transformed to the N,N-dimethylhydrazone 20 and alkylated with (S)-3-(tetrahydropyran-2'-yloxy)-1-iodobutane 14,27 to provide hydrazone 73. Selective deprotection using silica afforded the THPether 74, whereas use of 10% aqueous HCl released hydroxyenone 75.…”