Three‐Component Synthesis of 2‐Haloalk‐2(Z)‐en‐1‐ols via Tandem Haloalkylidenation—Aldehyde Addition.

Abstract Cr(II)-induced condensation of CCl 4 or CBr 4 with an aldehyde stereospecifically generates an ( E )-α-haloalkylidene chromium carbenoid which adds in situ to a second equivalent of aldehyde furnishing 2-haloalk-2( Z )-en-1-ols in high yield.