ABSTRACT
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.
ABSTRACT
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.
Subject(s)
Carcinoma, Merkel Cell/pathology , Fibrosarcoma/pathology , Skin Neoplasms/pathology , Aged, 80 and over , Carcinoma, Basal Cell/pathology , Carcinoma, Merkel Cell/metabolism , Carcinoma, Squamous Cell/pathology , Diagnosis, Differential , Female , Humans , Immunohistochemistry , Skin Neoplasms/metabolismABSTRACT
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. With time the lesions had become less obvious in the mother, so she and her daughter elected to have no treatment. Both mother and daughter were otherwise well. However, there have been rare reports of multiple trichoepitheliomas being associated with systemic conditions. Multiple trichoepitheliomas are inherited in an autosomal dominant manner and have been mapped to chromosome 9p21.
