Convergent diastereoselective preparation of adjacent quaternary stereocenters in an acyclic system.

The combined carbometalation-zinc homologation-allylation reaction of the resulting stereodefined 3,3-disubstituted allylmetal species with ketones allow the preparation of allylic vicinal diol derivatives in good yields with excellent diastereomeric ratios from commercially available alkynes. Two adjacent quaternary centers are formed with the concomitant formation of three new carbon-carbon bonds in a single-pot operation in an acyclic system. The bulky substituent of the ketone occupies a pseudo-axial position in the Zimmerman-Traxler transition state.

Highly diastereoselective preparation of homoallylic alcohols containing two contiguous quaternary stereocenters in acyclic systems from simple terminal alkynes.

The combined carbocupration of terminal alkynes followed by a zinc homologation and further reaction with ketones lead, in a single-pot operation, to the creation of homoallylic alcohols possessing two consecutive quaternary stereocenters with excellent diastereoselectivity.

Multiple trichoepitheliomas in a mother and daughter.

A 38-year-old mother and her 8-year-old daughter presented with multiple facial papules. In both cases, the papules had started to develop at about the age of 4-5 years. Biopsy of one of the mother's papules revealed a trichoepithelioma.