Table 3.

Substrate Scope of Enantioselective Allene Synthesis from Alkynyl Aldehydes^a

^aUnder each product the percent yield and enantiomeric ratio (e.r.) or diastereomeric ratio (d.r.) are given. Yields are isolated yields (0.4 mmol scale).

The e.r. or d.r. was determined by HPLC analysis using a chiral stationary phase. Abbreviations: Bn, benzyl; Ph, phenyl. See the Supporting Information for experimental details and stereochemical proofs.

^b3 equiv of boronate was used.

^c40 h.