Cyclohexenylboration of Aldehydes and Ketones with the Borabicyclo[3.3.2]decanes (BBDs).

Asymmetric hydroboration of 1,3-cyclohexadiene with 4R produces the allylborane 5RR as essentially a single diastereomer (i.e., no observable 5RS), and its addition to representative aldehydes provides 9RS (52-75%) with excellent selectivity (94-99% ee).

Borabicyclo[3.3.2]decanes and the stereoselective asymmetric synthesis of 1,3-diol stereotriads from 1,3-diborylpropenes.

The synthesis of mixed borabicyclodecane (BBD)-derived 1,3-diborylpropenes (trans-1) is described. These new bimetallic reagents are effective for the selective asymmetric allylboration first of ketones (or ketimines) and second of aldehydes (or aldimines). Formed as a thermodynamic mixture of trans regioisomers from cis-1 through a series of 1,3-borotropic shifts, only trans-1 undergoes the monoallylation of ketones.

B-allenyl- and B-(gamma-trimethylsilylpropargyl)-10-phenyl-9-borabicyclo[3.3.2]decanes: asymmetric synthesis of propargyl and alpha-allenyl 3-degree-carbinols from ketones.

Simple and efficient Grignard procedures are reported for the syntheses of B-allenyl-10-(phenyl)-9-borabicyclo[3.3.2]decane (1) and its B-(gamma-trimethylsilylpropargyl) counterpart (2) in both enantiomeric forms.