Silaboration of [1.1.1]Propellane: A Storable Feedstock for Bicyclo[1.1.1]pentane Derivatives

• Published in: Angewandte Chemie Vol. 132; no. 5; pp. 1986 - 1990
• Main Authors: Kondo, Masaki, Kanazawa, Junichiro, Ichikawa, Tomohiro, Shimokawa, Takumi, Nagashima, Yuki, Miyamoto, Kazunori, Uchiyama, Masanobu
• Format: Journal Article
• Language: English
• Published: 27.01.2020
• Subjects: Bor; Carbocyclen; Kleinringsysteme; Kreuzkupplungen; Silicium
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201909655

The silaboration of [1.1.1]propellane enables direct introduction of B and Si functional groups onto the bicyclo[1.1.1]pentane (BCP) scaffold in high yield under mild, additive‐free conditions. The silaborated BCP can be obtained on a gram‐scale in a single step without the need for column‐chromatographic purification, and is storable and easy to handle, providing a versatile synthetic intermediate for BCP derivatives. We also describe various conversions of the C−B/C−Si bonds on the BCP scaffold, including development of a modified Suzuki–Miyaura cross‐coupling reaction at the highly sterically hindered bridgehead sp3 carbon center of the BCP skeleton using a combination of highly activated BCP boronic esters, copper(I) oxide, and a PdCl2(dppf) catalyst system. Die Silaborierung von [1.1.1]Propellan ermöglicht die direkte Einführung von B und Si enthaltenden funktionellen Gruppen in das Bicyclo[1.1.1]pentan(BCP)‐Gerüst in hohen Ausbeuten unter milden, Additiv‐freien Bedingungen. Das silaborierte BCP kann in einem Schritt ohne Säulenchromatographie‐Aufreinigung im Grammmaßstab erhalten werden. Es ist lagerbeständig, einfach handhabbar und stellt ein vielseitiges Intermediat für BCP‐Derivate dar.