Wittig reactions of the ylide (Ph3P+CH-)2CH2 (I) with aliphatic aldehydes and ketones are described. A soln. of I in THF prepd. from (Ph3P+CH2)2CH2.2Br- was treated with an equimolar amt. of geranylacetone to give a stereoisomeric mixt. of II (norsqualene), b0.001 172-4 Deg, in 25% yield. III, b1 114-17 Deg, was similarly prepd. from I and cyclohexanone in 37% yield. I and propanal gave 49% (EtCH:CH)2CH2, b.142-5 Deg, contg. >90% cis, cis isomer, while the reaction in the presence of LiBr gave 35:50:15 mixt. of cis,cis,cis,trans, and trans,trans isomers, resp. [on SciFinder (R)]
Org.-Chem. Inst.,Univ. Heidelberg,Heidelberg,Fed. Rep. Ger.
written in German.
28230-92-4P; 28230-93-5P; 28284-80-2P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of)
Record created on 2006-03-03, modified on 2016-08-08