Enynone product

The enynone product from the above reaction can further react with an organo-zinc or borane reagent in the presence of Ni(COD)2 and occasionally a phosphine ligand to produce diastereoselectively the corresponding bicyclononene derivatives in good yield. When EtjSiH is employed, a similar product with an addition of a hydridic moiety is observed [168]. 

The same catalytic system (SeOi/TBHP) has also been used by Chabaud and Sharpless in the allylic oxidation of alkynes. The oxidation products resulting from the Se02-catalyzed allylic oxidation with TBHP are the allylic alcohol, the allylic diol, the allylic ketone, the ketol and the enynone (Scheme 127). The main product of the reaction is either the alcohol or the diol, depending on the substrate employed (together 76-100% of the whole yield). The yields of allylic oxidation products together range from 15 to 88%. From the observed results with unsymmetrical alkynes it could be concluded that the reactivity sequence for the carbon attached to the triple bond of alkynes is CH2 CH > CH3. 

Addition to an enynone (1). Cuprates, particularly higher-order ones, undergo 1,6-addition to 1 to provide the less stable (Z)-dienone 2 as the major product. The (Z)-stereoselectivity increases with the bulk of the transferred R group. The addition may involve an allenyl enol. Addition of QHjSLi to 1, however, provides (E)-dienones, possibly via an intermediate 1,2-adduct. 

B-Alkenyl- and B-l-alkynyl-9-borabicyclo[3,3,l]nonanes undergo smooth 1,4-addition to acyclic -unsaturated ketones. Cycloalk-2-enones do not yield any conjugate addition product. Furthermore the alkynylboranes react with acyclic /8-methoxy-a/8-unsaturated ketones to give conjugated enynones. ... 

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