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Upstream product

• 100-52-7 benzaldehyde 
• 87921-49-1 2-(1-bromo-2-propenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 

Relevant academic research and scientific papers

The hydroboration of propargyl bromide. Simple one-pot three-component routes to (Z)-1-bromoalk-1-en-4-ols and to anti-homoallylic alcohols

The hydroboration of propargyl bromide with dialkylboranes takes place regioselectively to give 3-bromoprop-1-en-1-yl dialkylboranes 13 which, upon quaternization with bromide ion, undergo a series of transformations into a number of allylic boron species. By a suitable choice of the experimental conditions it is possible to trap the reaction intermediates with aldehydes and to steer the process toward either the synthesis of (Z)-1-bromoalk-1-en-4-ols 6 or anti-homoallylic alcohols 8. Two one-pot three-component processes were developed based on a sequence of four reactions; preparation of dialkylborane and hydroboration of propargyl bromide are the first steps. Then, quaternization with TEBABr may be carried out either in the presence of the aldehyde when (Z)-1-bromoalk-1-en-4-ols 6 are requested, or in the absence of the aldehyde in order to allow the formation of γ-substituted allyl borane 18 which, successively, adds to the aldehyde affording antihomoallylic alcohols 8.

Stereoselective Synthesis of Alcohols, XXII. E/Z-Selectivity on Addition of α-Substituted Allylboronates to Aldehydes

α-Heterosubstituted allylboronates 7 are prepared.Addition of 7 to aldehydes results in E/Z-isomeric homoallyl alcohols 13 and 14.The reasons for the predominant formation of the Z-isomer 14 are discussed.The Z-bromo olefins 16 and 20 obtained in this way serve as starting point for chain extension or formation of δ-lactones 21.

Z-SELECTIVE FORMATION OF SUBSTITUTED HOMOALLYL ALCOHOLS

The α-substituted allylboronates 4 add to aldehydes giving with high Z-preference the homoallyl alcohols 1.The Z-vinyl bromides obtained were further converted into δ-lactones.