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DOI: 10.1055/sos-SD-109-00525

Tobrman, T.Science of Synthesis Knowledge Updates, (20241137.

The preparation of substituted 1H-phospholes by 1,1-carboboration of dialk-1-ynylphosphines has already been mentioned in Section 9.14.4.[‌34‌] Later, a detailed study of the reaction mechanism revealed the formation of zwitterionic salt 13 under mild reaction conditions in 44% yield from dialkynylphosphine 12. On the other hand, performing the cyclization reaction at elevated temperature directly produces the 1,1-carboboration product 14 in 78% yield (Scheme 7).[‌35‌] Further studies have shown that 1,1-carbocyclization can be carried out in the presence of a frustrated P/B Lewis pair.[‌36‌] A combination of 1,1-carboboration and a Suzuki–Miyaura reaction allows for the synthesis of dithienylphospholes.[‌35‌,‌37‌,‌38‌]

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