A one-pot diastereoselective synthesis of cis-3-hexene-1,6-diols via an unusually reactive organozinc intermediate.
A highly diastereoselective method for the synthesis of cis-3-hexene-1,6-diols has been developed. This new reaction proceeds with excellent control of diastereoselectivity over four stereocenters and the double bond geometry. The diols are made in a one-pot procedure involving hydroboration of a terminal alkyne and transmetalation to zinc to give a divinylzinc intermediate. This intermediate undergoes reductive elimination, forming a C=C bond. In the absence of a trapping reagent, diene is liberated (70% yield); however, in the presence of ketones or aldehydes, the proposed intermediate metallocyclopentene is trapped via a double insertion of the carbonyl substrate. Workup provides the diols in 47-86% yield.
García
Celina
C
P. Roy and Diane T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104-6323, USA.
Libra
Eric R
ER
Carroll
Patrick J
PJ
Walsh
Patrick J
PJ
D000438:Alcohols / Q000138:chemical synthesis*; D000447:Aldehydes / Q000737:chemistry; D000475:Alkenes / Q000138:chemical synthesis*; D000480:Alkynes / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D015032:Zinc / Q000737:chemistry*
D000438:Alcohols; D000447:Aldehydes; D000475:Alkenes; D000480:Alkynes; D007659:Ketones; D009942:Organometallic Compounds; C117224:1-hexene; D015032:Zinc; C454811:diethylzinc