Chiral auxiliaries dioxaborolane

Use as a Chiral Auxiliary Synthesis of Cyclopropylboronic Acids. The chiral dioxaborolane unit can also be used as an effective chiral auxiliary in the synthesis of enantiomerically enriched cyclopropylboronic acids. For example, 1-alkenylboronic esters bearing the tetramethyltartramide group undergo diastereoselec-tive cyclopropanations to afford the cyclopropylboronic acid (eq 11). These products can be used for in situ Suzuki coupling reactions or can be oxidized to produce 2-substituted cyclopropanols. 

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