Homoallylic alcohols Crotyldiisopinocampheylborane

S)-2-Ethoxy-4-isopropyloxazoline, 129 Homoallylic alcohols Crotyldiisopinocampheylborane, 86 Dichlorobis( 1 -phenylethoxy) -titanium(IV), 12 Organotitanium reagents, 213 Tin(II) trifluoromethanesulfonate, 301 Homopropargylic alcohols Bis(2,4-dimethyl-3-pentyl) tartrate, 36... 

Treatment of ( )-crotyldiisopinocampheylborane, derived from (-r)-a-pinene, with aldehydes furnishes, after oxidation, the ann-alcohols with 95% enantioselectivity. The reaction of ( )-crotyldiisopinocampheylborane, derived from (-)-a-pinene, with aldehydes yields the enantiomeric anr/-alcohols, also with 95% enantioselectivity. By this approach, using cw-and trans-l-hni ne, and (+)-a-pinene and (-)-a-pinene, all four stereoisomeric homoallyl alcohols may be obtained. 

The synthesis of 108 began with homoallylic alcohol 114. Protection of the alcohol was followed by ozonolysis to give aldehyde 115. Reaction of the aldehyde with Z-crotyldiisopinocampheylborane, a chiral crotylborane, gave 116 in high yield with excellent diastereo- and enantioselectivity (see Calcimycin-13... 

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