Cyclopropanations allylic alcohols, cyclohexane

The A, A -bis(arenesulfonyl)cyclohexane-1,2-diamines used as chiral controllers (see also Houben-Weyl, Vol. E21, pp 1327, 3895) can also be employed as their aluminum complexes to catalyze the cyclopropanation of allylic alcohols with diethylzinc and diiodomethane. ° The bis(sulfonamide)aluminum complex was first prepared in situ in 1,2-dichloroethane and after removal of the solvent in vacuo, cyclopropanation was carried out in dichloromethane at — 20 °C. The enantioselectivities are similar to those obtained with the chiral zinc catalyst described above. However, the most characteristic feature of the chiral aluminum complex catalyzed reaction is that no decrease in the enantioselectivity was observed even at a higher concentration. An electron-withdrawing group on the benzene ring of the sulfonamide or the... 

The effect of solvent was also studied and complexing solvents such as THF or Et20 inhibited the cyclopropanation reaction. Furthermore, the presence of an unprotected allylic alcohol was found to be essential, since the methyl or benzyl ether derived from cinnamyl alcohol afforded almost racemic cyclopropanes. This method has also been extended to the enantioselective cyclopropanation of vinylsilanes and -stannanes (Scheme 4) [13]. The corresponding optically active silyl- and stannyl-substituted cyclopropyhnethanols were obtained in the presence of the chiral N,iV-bis(p-nitrobenzenesulfonyl)-l,2-cyclohexane-diamine 9. 

Scheme 6.28. Asymmetric cyclopropanation of allylic alcohols (a) Using a glucose-derived auxiliary [106] (b) A cyclohexane diol auxiliary [107].

Systematic transmission spectroscopic studies of the transformations were carried out on the systems allene, propene, cyclopropane, zsopropanol and acetone over NaM,HM and NaHM [113-117], 1-butene over NaHY [117,118], allene, propene and cyclopropane over NaHY and NaHZSM-5 [116,117,119-122],neopentane over NaY, NaHY,NaHM and NaHZSM-5 [119,123,124],cyclohexene over HZSM -5 [ 119], 1 -hexene, cyclohexane, cyclohexene, cyclohexadiene and benzene over NaHY and NaHZSM-5 [117,125], allyl alcohol, acrolein and allene over HZSM-5 [ 126], allene and propyne over nonacidic zeohtes NaA, CoNaA, CoNaX, NaY and NaHY [121] and benzene, toluene, ethylbenzene, and cumene over HZSM-5 [127]. 

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