A Novel Application of Sodium Borohydride for the Regiospecific and Stereoselective Reduction of Conjugated Alkadiynes

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• In deference to the suggestion by a referee, we have conducted the reduction using sodium borohydride in MeOD. There is no incorporation of deuterium at carbon-2 but incorporation occurs at carbon-3(as expected by us and the referee) as well as at carbon-1. (This latter is from a prior exchange of the acidic hydrogens at carbon-1)
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• The predominant formation of the cis isomer is in line with our ealier work in which we have outlined the less hindered approach of the anion to the incipient allene resulting in kinetic control of product distribution. See: Thyagarajan, B. S.; Chandler, R. A.; J. Chem. Soc., Chem. Commun., 1990, 328–330. Thyagarajan, B. S.; Wood, B. F. Jr. and Swynnerton, N. F., Phosphorus Sulfur, 1985, 21, 357
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• In response to the referee's suggestion, we have also carried out the reduction of IX to the corresponding diene XI. (See experimental)
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