Stereospecific inversion of secondary tosylates to yield chiral methyl-branched building blocks, applied to the asymmetric synthesis of leafminer sex pheromones
摘要:
All four of the possible stereoisomers of 5,9-dimethylheptadecane, the major sex pheromone component secreted by female moths of the mountain-ash bentwing (Leucoptera scitella), were synthesized by the coupling of two chiral blocks with a methyl branch at the 2- or 3-position. The blocks were prepared by applying the stereospecific inversion of secondary tosylates, which were derived from (R)- and (S)-propylene oxide, and their enantiopurities were confirmed by chiral HPLC analysis. (c) 2012 Elsevier Ltd. All rights reserved.
A highly efficient asymmetric conjugate addition of methylmagnesium bromide (MeMgBr) to α,β-unsaturated esters catalyzed by copper(I) iodide-tolyl-BNIP (CuI-Tol-BINAP) is described.
We're bringing sexy back: The highly efficient introduction of stereogenic centers bearing methyl group by conjugate addition of RMgBr to α,β‐unsaturated esters has been employed in the total syntheses of two sex pheromones (see scheme). Binap=[1,1′‐binaphthalene]‐2,2′‐diylbis(diphenylphosphane).