Synthesis Ideas

A journal of proposed syntheses by students of Bob Hanson in

Chemistry 247B, Fall 2000


Notice to Authors Target Compounds A-E
And here are the results. Congratulations to all successful authors!
a-mg.htm
Comments:Several other excellent syntheses were received, but only this one is of the correct compound! Honorable mention (and credit) goes to: a-njhale.htm a-pc.htm a-rsthkr.htm
b-aspsvh.htm
b-bc.htm
b-jgrhab.htm
b-mg.htm
b-njhale.htm
Comments:Note how most of these syntheses avoid regioselectivity issues by avoiding addition to internal alkenes or alkynes.
c-aspsvh.htm
c-bc.htm
c-jgabrh.htm
c-mg.htm
c-njhale.htm
c-prmsmd.htm
c-rsthkr.htm
Comments:Note how five of these seven syntheses nicely avoid regioselectivity issues by generating the trans-alkene from the alkyne instead of doing an elimination. There is some question whether the dianion from an acetylenic alcohol will be alkylated at C or O, but that just makes some of these proposals more interesting!
d-njhale.htm
d-pc.htm
d-rsthkr.htm
d-rvhg.htm
Comments:Of these syntheses, the first three are quite plausible. The last might have some compatibility issues. Again, will the dianion of an acetylenic alcohol alkylate on C or O?
e-njhale.htm
e-pc.htm
e-rsthkr.htm
Comments: All of these suffer from regioselectivity problems associated with the tri-substituted double bond. This is a very difficult problem in organic synthesis.