# Can secondary alkyl halides be used in the Corey–House synthesis?

I've been told by my teacher that the Corey–House synthesis cannot proceed with secondary alkyl halides; they will prefer to undergo elimination over $$\mathrm{S_N2}$$ substitution. [used as the pseudo halide, not the diorganyl cuprate.]. My book, however says that secondary alkyl halides do undergo the reaction. A quick google search on Wikipedia says:

[...]RX, R = methyl, benzylic, allylic, primary, or cyclic secondary alkyl, aryl, or alkenyl

These seemingly varied responses have really left me rather confused. Is the applicability different for different secondary halides? If yes, why? And if no, then which is the correct answer?

Secondly, my teacher also tells me that in R-X, using Br, Cl, or F as the halogen will not produce a satisfactory yield. Again, Wikipedia goes on to say:

[...] X = Br, I, OTs, or OTf; X = Cl is marginal.

Again, could anyone help me out in resolving these differences? I've never really had the opportunity to see these reactions in the lab, so I feel that someone with real experience would be able to help me out.

• Please use "primary", "secondary", "tertiary" - degree symbols are shorthand notation, not proper terminology. – orthocresol Apr 4 at 16:47
• @orthocresol thanks for the heads-up. Will do so from next time. – C_Lycoris Apr 5 at 7:50