Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.
DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.
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)]
Gabor Laurenczy, Raymond Roulet